


An Arrival in Underfell

by SoloShikigami



Category: Undertale (Video Game)
Genre: Alternate Universe, Babybones (Undertale), Domestic Fluff, Fluff
Language: English
Status: Completed
Published: 2020-03-08
Updated: 2020-03-09
Packaged: 2021-03-01 04:09:20
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 21,834
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23059030
Author URL: https://archiveofourown.org/users/SoloShikigami/pseuds/SoloShikigami
Summary: Papyrus and Sans are on patrol when they come across the last thing they ever expected - a baby skeleton!
Comments: 21
Kudos: 109





	1. The Arrival

**Author's Note:**

> Written for Silverwolf715

Papyrus growled; it had been a boring day. Hell, it had been a boring week. While Undyne would certainly be pleased to hear from her head of the Snowdin Sentries that there had been no trouble to report, no unusual goings-on to speak of, she would be disappointed over the lack of human sightings. Papyrus was too.

For Asgore's sake, he didn't even have any gossip!

"THIS IS UNACCEPTABLE!" Papyrus shouted into the forest. "THERE MUST BE A CHALLENGE WORTHY OF THE GREAT AND TERRIBLE PAPYRUS!”

“Chill, Boss,” Sans grumbled, shuffling along in the snow next to his brother. He had been forced out on the patrol with him for “horrible puns and boondoggling.”

“A SKELETON AS GREAT AS I IS NOT SUSTAINED BY PUZZLE CALIBRATIONS ALONE!" Papyrus continued, as if Sans had said nothing. “IF I AM EVER GOING TO BE A CAPTAIN IN THE ROYAL GUARD, I NEED-!”

"Aaaaaahhhhh!"

Papyrus stopped. He was unsure if he had actually heard something or his mind was playing tricks due to boredom.

"Wwaaaaahhh!!"

The wail was definitely real, and the two brothers exchanged a look of confusion before nodding and splitting up to start searching.

They didn't have to go too far.

"SANS! IT'S OVER HERE!" Papyrus shouted.

Sans quickly made his way to where his brother stood. He was looking down at a light blue lump in the snow. The fussing noises it was making were all too familiar; Sans knew exactly what it was before he saw it.

"Sans?" Papyrus said in a quieter tone.

"Yeah?"

"Is... is that a baby?"

"Sure is."

"Do skeleton babies come from the ground?"

Sans kept himself from laughing. It was a fair assessment, since the ground around the baby tucked in the bundle of light blue blankets was disturbed.

"Yeah, sure bro," he answered, still a little dumbfounded and not willing to have a conversation about the birds and the bees at that moment.

"Well, pick it up!"

"No way, Boss, we don't know where they came from!"

"The ground, obviously!"

"But what if they belong to someone?" Sans started shifting his weight from one foot to the other nervously.

"IMPOSSIBLE! WHO WOULD LEAVE A BABY OUT IN THE SNOW ALL ALONE!"

Sans hated to admit it, but Papyrus had a point.

Papyrus' eyes suddenly went wide. "SANS! IT IS JUST LIKE US! THIS BABY HAS NO PARENTS JUST LIKE WE DON'T HAVE PARENTS!" Papyrus gasped in realization, "WE CAN BE ITS PARENTS!"

"What?!"

Papyrus bent down and picked up the baby under their arms. The baby stopped crying, only letting out a small little whimper as their breath hitched.

"Heh, I think they like you," Sans said, grinning.

"OF COURSE IT DOES! WHO WOULDN'T BE IN AWE IN THE PRESENCE OF SUCH A MALEVOLENT MONSTER SUCH AS MYSELF?!"

The baby sniffled and wriggled uncomfortably, starting to fuss again.

"WHY ARE YOU SO SQUIRMY? STOP IT AT ONCE!" Papyrus demanded.

The baby broke out into a wailing cry.

"Heh, I don't think they liked that, Boss," Sans said with a chuckle.

"SILENCE! I, THE TERRIBLE PAPYRUS, ORDER YOU TO CEASE YOUR CRYING IMMEDIATELY!"

The baby only cried harder.

"SANS! WHAT DO I DO?!? I THINK I BROKE IT!"

Sans burst out into laughter; he had been trying to stifle his amusement, but now it was too much. He had never seen his brother look so flustered before, and while he would have loved to continue watching him freak out over the baby, the tiny, wailing waif was clearly in distress.

"Okay, okay, just, heh, just give them to me," Sans said, sobering his laughter enough to take the baby carefully from his brother's slightly shaking hands.

For a brief moment as Sans adjusted the baby and cradled them in his arms, he was transported back in time - back when he had another set of fussing baby bones in his arms. He felt an odd sensation around his mouth as it turned upwards into a smile; the first true, genuine smile that he'd had in a very long time.

"Shh, shh," he hushed the little one and rocked them gently. "S'okay, baby bones, I got ya."

Papyrus watched in awe; not only was the baby calming quickly in the more certain and sure arms, but to witness this odd transformation in his older brother from the useless, lazy, apathetic bag of bones who made insufferable puns to this caring, nurturing monster who murmured softly and gazed upon this new life with an odd look in his eyes was something he never imagined he would ever see.

Papyrus felt an odd tightening in his soul - suddenly feeling something very odd towards his brother.

"What magic did you use?" Papyrus demanded when the baby calmed and began to yawn and doze in Sans' arms.

Sans chuckled. "Love, Boss, just a little love."

Papyrus knew Sans didn't mean Level Of ViolEnce.

"So, what do we do now?" Papyrus asked, feeling quite lost and unsure for the first time he could remember.

Sans sighed. He didn't know where this baby had come from; to find a monster baby all alone was unusual in and of itself, but a skeleton one? Even more unusual.

"Let's get them back home, Boss. We're gonna have to make some adjustments when we get there."

* * *

The baby didn't nap very long. As a matter of fact, they awoke just as Sans finished tucking them in on Papyrus' bed - Sans' bed was deemed far too unsatisfactory for a baby to sleep in.

"Or any monster with any standards," Papyrus had muttered.

When the baby awoke, they stared up at the brothers with two bright light orbs in their eye sockets. Their little face broke into a wide grin and they began to gurgle and giggle.

"Are their eyes supposed to look like that?" Papyrus asked, a little surprised as he had never seen any being with blue eyes, or any eyes that were that bright.

"Well, this one does apparently," Sans said. "You know, we gotta call the little one something."

Papyrus huffed. "It should be able to tell us their name!"

"I think goo-goo and ga-ga is about the extent of their vocabulary, Boss," Sans said with a tolerant sigh. "Look, how about Blue?"

"How do you figure?"

"On account of those big ol' blue eyes?"

Papyrus eyed his brother for a moment, mostly searching for a pun, and finding none he nodded.

"VERY WELL!" Papyrus bent and picked up the baby in the same manner he did before. "YOU SHALL BE KNOWN AS BLUE THE TINY!"

Blue wailed.

"Boss, you gotta tone it down," Sans said. "Also, you can't hold them like that, it makes them feel unsafe."

"What am I supposed to do then, jackass?" Papyrus snapped, lowering his voice but doing little else to change otherwise.

"Well, they seem to be able to hold up their head, here," Sans moved over and supported Blue's back for a moment. "Put this hand under their bottom, and hold them closer to your body."

Sans guided Papyrus and the baby, ignoring the incredibly uncomfortable look Papyrus had on his face. Papyrus went with it and the baby naturally leaned on his chest.

"Now, put your other hand at their back, like this," Sans instructed. "Good, now just keep your hand at their back firmly, remember, it's for support."

Papyrus only nodded. Blue had stopped fussing and was now snuggling happily against Papyrus.

"Sans?" Papyrus whispered.

"Yeah?"

"Am I doing this right?"

Sans chuckled. "Yeah, bro, you are."

Papyrus looked very pleased and just slightly adjusted his arms to be more comfortable, and he felt that as his comfort level rose, so did the spirits of the baby.

"Now what do I do?" Papyrus asked.

Sans scratched the back of his head. "Dunno, I mean, they're not tired, I don't think that they're hungry, so, just hold them?"

Papyrus glared at Sans. "This is what having a baby is all about, then? Just holding them?"

"Until they want something else or are a little older, pretty much," Sans looked at him with amusement. "The hell did you think?"

"We should be training! This is wasted time!"

"Bwa ha ha! Training? For what?"

"For the Royal Guard, of course! Our child will be the strongest soldier the guard has even seen!"

Sans blinked. "Our child?"

"Naturally! We are both going to raise this child, are we not?"

"Oh, well, yeah, I guess," Sans scratched the back of his head.

Papyrus frowned at Sans. "What is wrong? I know that look."

"Just... don't want people getting the wrong idea."

"To hell with whatever ideas they have!"

Sans sighed and shrugged. "I guess you're right, Boss."

Blue looked up at Papyrus and raised a tiny hand and started to none-too-gently smack at his mandible.

"Buh buh, pffft," Blue babbled.

Papyrus looked down. "What is it, Blue?"

Blue giggled and slapped at his jaw again.

"Answer me, Blue!"

"Bah buh buh buh bah!" the baby continued to babble, their voice going higher with each noise.

"Sans! Why does Blue not answer me properly?!"

"Baby, Boss, Blue is a baby, they can't speak yet," Sans said tolerantly.

"Unacceptable!" Papyrus shifted his hands so he was holding Blue under his arms again, but kept them close instead of at arm’s length, lifting the little skeleton enough to look into their eyes. "Blue! You shall learn to speak! In order to train you properly, you must be able to obey my command and respond to my orders! How else am I going to know what you wan-!"

Blue had been looking at Papyrus curiously, then they stuck a hand between the sharp teeth and grabbed at the lower jaw from the bottom row of teeth.

"Ah! Ah! HEL! HAN ISH IN MAH MOU!"

Sans doubled over with laughter, which made Blue laugh, and Papyrus controlled himself to not tear the baby away from him, lest his teeth either hurt the child or some of his teeth went with the tiny hand.

Suddenly, Blue let go of Papyrus and they made a face. Papyrus then held Blue at arm’s length again, and he was about to scold the child when something made his own face twist.

"Sans, what is that smell?" Papyrus asked.

"Ah, guess Blue is still too little to figure out what to do with the excess magic." Sans explained. "Here, lemme take the little one."

Papyrus didn't question and handed the baby to his brother and followed him back to the bed. Sans put Blue down and started to unsnap the pajamas along their leg. Papyrus looked away, feeling awkward and a little useless, but his attention was snapped back when his brother gave a small cry of surprise.

"WHAT IS IT?" Papyrus asked worriedly, finding Sans' face wet with what was... blue magic?

Sans sighed and wiped his face as he looked down at Blue, who cooed and giggled up at him.

"Heh, look like Blue identifies as a boy, unless he says otherwise later," Sans muttered. "Hand me a towel, Boss?"

Papyrus put two and two together and laughed.

* * *

It took some looking, a bit of bribing, and a touch of innovation, but the skeleton brothers were able to get a couple of baby bottles, a high chair, and a crib for little Blue. Thankfully he seemed to be past needing to feed off of a mother’s magic, but he was far from skilled enough to drink from a cup.

“This was so much easier when you were a baby,” Red grumbled as they dragged pieces of their new furniture inside, which was difficult as one of them had to hold on to Blue.

“I CANNOT IMAGINE YOU DOING THIS ALL ON YOUR OWN!” Papyrus snapped. “LAZYBONES THAT YOU ARE!”

Red chuckled. “I sure as hell wasn’t going to let anything happen to my baby bro. I couldn’t have been that lazy if you made it this far.”

“I WAS NEVER THAT HELPLESS!”

“We all were, Boss.”

Papyrus tossed a glare at Sans, but when he looked back and saw him cradling Blue, who sat happily in the crook of one arm chewing a washcloth and his other arm struggling to keep hold of one of the sides of the crib, Papyrus cleared his throat, his face softening ever so slightly.

“Blue looks hungry,” he grumbled in a lower toned voice. “Can you manage filling a bottle?”

“What about the crib, bro?”

Papyrus turned and gently took the other piece from Sans, adjusting the pieces he was carrying. “I’ll be fine. Take care of Blue.”

Sans watched Papyrus continue up the stairs easily enough, though maybe a little slower. He took up the chance to get out of hiking up and down the stairs and the possible headache of putting together a crib in favor of adjusting Blue in his arms.

“C’mon, ya lil’ brat,” Sans said, grinning widely at Blue and holding him up so he giggled. “Let’s get you some chow.”

He set Blue down on the kitchen floor close by, deciding that he would be all right for the few minutes it would take for him to clean up and fill one of the bottles with some milk.

“Damn, these things look pretty dirty,” Sans murmured, eyeing the edge and curves in the bottle. “I hope I can get them clean. Can’t believe it took nearly ten gold for one bottle and they couldn’t be bothered to clean the damn thing.”

Sans ran the hot water, hoping that a few rinses would do the trick, glancing down at Blue who was making clacking sounds by smacking the slightly warped linoleum with his palms, babbling.

“Heh, mebbe you’re cut out for drumming,” Sans said. “That’d please Paps, you raising hell with a drum set. He’d probably tie me up and let you use my skull as your drum.”

Blue continued to smack the floor, his babbling reaching screeching volumes, not paying any attention to what Sans was saying.

“Seems like you go the singing down, too, maybe you’ll make the first monster metal band.”

“ _pppffffbbbbhhtttt!_ ” Blue said in reply.

“Okay, maybe too soon,” Sans said with a shrug, returning his attention to washing the bottle.

It took Sans a little longer than he thought it would, but he figured it was okay as long as Blue continue to be entertained with smacking the floor and babbling, but as he finished filling the bottle he realized it was quiet. He looked at the floor and sure enough, Blue wasn’t there.

“Hey!” Sans cried out in dismay. He rounded the doorway into the living room and stopped short, nearly tripping over the baby sitting on the floor. “Whew, thank the stars, what are you doing, baby Blue?”

He looked down to find those big baby blue eyes looking at him almost pointedly, a familiar sock in one hand as he began waving it about with another round of babbling.

“Hey, there’s a reason it’s there,” Sans said, defending himself as he bent to pluck it out of Blue’s hand, then he tossed it back on the floor, and scooped the little one up.

Blue immediately began squirming and fussing.

“No, Blue, leave the sock,” Sans said patiently, returning to the kitchen and grabbing the bottle from the counter. “I got something better for ya.”

He stuck the bottle into Blue’s mouth, and Blue immediately got the idea and began suckling.

“Awesome.”

Sans moved them into the living room, but before he parked on the couch, setting Blue in his lap with the tiny back to his chest, and he called upstairs.

“How you doing, Boss?”

“REMIND ME TO BREAK DOGGO’S TREATS IN HALF!” Papyrus snarled. “THESE TOOLS ARE SUBPAR AT BEST!”

“What an asshole,” Sans murmured mostly to himself, shaking his head. Doggo was usually trying to pull a fast one on the skeleton brothers. “Don’t worry, Papyrus, we’ll pay him back eventually, always do.”

“ARE YOU NEGLECTING YOUR DUTIES TO THE BABY?!”

“Of course not! The kid has a bottle, he’s as happy as Mettaton with a new chainsaw.”

There was a slight grunt as Papyrus turned back to his task. Sans sighed and returned to his, watching Blue as he happily drank his milk.

Sans couldn’t help brushing the backs of his fingers against Blue’s cheekbone, admiring the softness of them and the pure white that they still had. His mind kept flashing back to when Papyrus was a baby and he sighed.

“Well, hopefully I don’t screw this up this time,” Sans mumbled.

Blue looked up at him, still drinking, his eyes shining bright with trust. Sans smiled back down at him.

“Don’t worry, little guy, we’ll make sure nothing happens to ya.”

* * *

Papyrus sighed as he put the screwdriver back in the small bucket that they used to keep their tools. The crib was a lot harder to put together than he had anticipated, but he was certain he did it correctly.

“I hope Blue is grateful for all the trouble we have gone through to make sure he has everything he needs,” Papyrus said as he came downstairs. “Sans, the crib is finished, so we should be able to-!”

He stopped at the sight on the couch. The baby bottle was empty and on the floor, Blue was laying on his front on Sans’ belly, and both were sound asleep. Sans had both hands protectively on Blue’s back, keeping the little one steady as they slept.

Papyrus sighed and shook his head as he picked up the bottle. “A pair of lazybones, the both of you.”

The tall skeleton took a moment to wander into the kitchen. It was still surprisingly clean, he took a moment to wash the bottle and set it aside to dry. He leaned in the doorway between the two rooms; he didn’t have any work duties, the house was clean, the crib was built, he wasn’t hungry… Surprisingly, Papyrus was tired. But going upstairs to sleep in his room by himself didn’t feel right.

He went over to the couch and carefully lifted Sans’ back and slipped onto the couch behind him, adjusting them so Sans was lying between his legs, putting a pillow between Sans’ head and the space above his own pelvis. The baby fussed only slightly, which made Sans begin to stir.

“Boss?” Sans murmured, opening bleary eye-sockets to look up at his brother.

“Shh, go back to sleep,” Papyrus murmured, putting one hand next to Sans’ on Blue’s back, curling the other around his brother protectively.

“Heh, okay.”

The afternoon went on, cool and quiet, as the three skeletons slept it away.


	2. Baby Blue Can Train, Too!

**Summary for the Chapter:**

> Blue starts his training, Sans learns of an interesting rumor, and Papyrus learns how hard his brother had worked in the past and how easy it is to hurt him.  
> *This fic is not a fontcest fic, anything alluding to it is a play off of when siblings are mistaken for lovers, and yes it happens XD

“What the hell is the meaning of all of this?” Sans growled.

“Just because you are lazy does not mean I am going to allow our brother to fall into the same lifestyle!” Papyrus declared. “I am a skeleton of standards and no child of mine is going to waste time sleeping all day!”

Sans scrubbed his hand over his face with an annoyed sigh. “Baby, jackass, Blue is a damn _baby_!”

“AND AS SUCH YOU WILL WATCH YOUR LANGUAGE AROUND HIM!”

Sans grumbled and shoved his hands into the pockets of his jacket and sat down where he stood. Papyrus, who had been holding Blue against his hip, lifted the baby into the air with a cackle.

“NYEH HEH HEH! You see that, Blue?! The Terrible Papyrus is always victorious!”

Blue giggled; he had gotten over his apparent fear of heights and now trusted Papyrus to handle him in such a playful manner.

As irritated as Sans was, he couldn’t help smiling, his bad mood fading away under seeing Blue and Papyrus so happy. He took a look at what had apparently kept Papyrus occupied over the past two weeks.

The snow in the area was packed down, making it much more stable to walk on. There were lines drawn into the snow, though Sans guessed that they might be difficult for someone to see from up high, because he only noticed them now that he was sitting. On one end of the area was the training dummy he remembered seeing outside of Undyne’s house. He wondered if it was still possessed.

“Now then, Blue! If you are to become part of the Royal Guard one day, training is of the utmost importance!” Papyrus said, his tone changing into a lecturing one as he began walking towards the dummy. “The first thing you are going to learn is how to defeat your enemy!”

Papyrus set Blue on his feet, but the baby promptly dropped right onto his bottom.

Sans laughed. “How do you expect the kid to fight, Paps? He can’t even stand up!”

“Do not listen to him!” Papyrus said to Blue with a sniff. “He is being negative and unsupportive!”

“I’m being realistic,” Sans said with a sigh, moving to lie on his side with his head propped up on one hand. “Maybe you ought to just read some books to the kid, like your training manuals.”

“They are far too advanced! Besides, nothing trains you better than doing!”

Blue leaned forward on his hands and started gripping at the snow.

“See? He is thirsty for blood!” Papyrus said gleefully. “Look at him clawing the ground in anticipation!

Sans looked over at Blue as he babbled, fingers still working through the snow in fascination.

“Yup, better watch that bloodlust, kiddo,” Sans murmured.

“Yes, Blue, feel the rage building inside you,” Papyrus continued. “Once you feel it, attack the dummy with all of your might!”

Papyrus pointed dramatically at the dummy. Blue didn’t even look up.

“Blue? Are you listening?! Destroy the dummy!”

Blue giggled, patting the ground, making some of the snow fly up, some hitting Papyrus in the face. Blue then grabbed a fistful and shoved the snow into his mouth.

“Perhaps you need some assistance,” Papyrus said with a slight cough, wiping the snow from his cheekbone.

Sans barely contained his amusement as Papyrus picked Blue up and brought him closer to the dummy. Papyrus made a bigger show of pointing to the dummy to get Blue’s attention.

“There, Blue! Now, attack!” Papyrus exclaimed.

Blue’s attention was had; he looked at Papyrus, then he looked at the dummy, and then back at Papyrus. He leaned forward towards the dummy.

“Yeah, come on, kid,” a raspy voice came from the dummy. “I gotta make a living somehow.”

Blue leaned back towards Papyrus, making an uncertain sound and looking up at the other skeleton.

“Go on! Show that dummy who’s boss!” Papyrus said, clenching a fist and grinning maliciously at the mannequin. “Well, I’m the boss, but that is beside the point!”

“Feh, an’ you call _me_ the dummy!” the raspy voice sneered.

“Hmph! Go on, Blue, tear it apart!”

“Go for it, kid, I’m rootin’ for ya!” Sans called.

Blue looked up at Papyrus again, then over to Sans, and then back at the dummy. The little skeleton’s eyes finally set in determination and he moved to crawl towards the dummy confidently.

“Yes, yes! Do it, Blue! Make your big brother proud!” Papyrus said, bouncing in his spot excitedly.

Blue crawled forward steadily.

“What even is this?” the dummy snarled. “It barely comes up to my middle! It can’t even walk!”

Blue didn’t seem to be dissuaded by the dummy’s words, and when he finally reached it, he reached up to grip the bottom edge and pull himself up to his feet.

“What are you going to do now, bone boy?” the dummy cackled nastily. “Drool on me? Launch some spit-up? Or maybe-?!”

Blue stepped one foot very firmly on his base, catching Mad Dummy’s full attention. They stared into each other’s eyes for a moment. Blue’s face then broke into a wide grin, his arms slipping around the soft body as much as he could and he lay the side of his head against Mad Dummy with a soft coo.

Sans blinked, and so did Papyrus. Mad Dummy was stunned into silence.

After a few moments, Papyrus cleared his voice. “Ahem, yes, well, I suppose that is one way to subdue your enemies. Good job, Blue.”

Sans rolled face-down into the snow, his laughter muffled.

Mad Dummy would remain in a stunned silence for the rest of the day.

* * *

“So… what is the story with that baby skeleton you and your brother have been carrying around?”

Sans looked up from the items he had put on the counter. “What makes you think there’s some sort of story?”

The bunny rolled her eyes, crossing her arms as she leaned over the counter to get face to face with Sans. “Don’t play stupid with me, Sans. I don’t know what you’ve told your brother, but babies don’t just pop up from the ground.”

“Heh, then it sounds like you found out exactly what I told him,” Sans said, and he made his eye flicker with magic. “And if you say otherwise to him, I will make you regret it.”

“Back off, bones,” the shopkeeper said with a bored sigh and another roll of her eyes. “You want to lie to your brother, that’s your business. I guess the other rumors aren’t true, then.” She stood up straight again, glancing over the items Sans set before her. “Is this it?”

“Yeah, that’s it,” Sans muttered. He tilted his head. “What rumors?”

The shopkeeper smirked. “Ten gold for everything, and five for the gossip.”

Sans narrowed his eyes at the rabbit monster, and she just hummed serenely as she began to pack up his items into the old cloth bag he had brought with him. He shifted his weight back and forth, weighing his options, then he sighed and pulled out the coins and dropped them on the counter. She picked up the coins and counted them.

“This is only thirteen,” she said with a slightly sour expression.

“How about this, dollface,” Sans said, taking the bag and slinging it over his shoulder. “You keep all that no matter what, and I’ll give you the other two gold if I find the rumors entertaining.”

The shopkeeper scowled, flipping the coins between her fingers for a moment, and then sighing, deciding it was worth a shot.

“Well, the rumor is the baby is yours and Papyrus’ love child,” she said.

Sans’ eye widened. “Really now?”

“Yup. You gotta admit that it makes sense, what with you both not only being the only skeleton monsters in town, but the fact that you two don’t really hang around anyone else.”

Sans scoffed. “Who the hell would we hang around with? Only losers in this town. Who the hell started that messed up rumor?”

The rabbit shrugged. “Fuck if I know.”

Sans nodded, reached into his pockets, and threw three gold onto the counter. “That was entertaining. Thank, Bunbun.”

“Up yours.”

* * *

“WHAT DO YOU MEAN HE HUGGED IT?!?”

Sans winced as he shut the front door. He could hear Undyne’s scream through Papyrus’ phone, and he was in the kitchen. Blue was seated in the high chair, which was visible from the front door, and he seemed busy with the few toys that the brothers were able to find, but he looked up and grinned at Sans.

“Hey kiddo,” Sans said, coming into the kitchen and caressing the baby gently on his head.

“Bah bah bah bah!” Blue babbled.

“Same to you,” Sans gave him a wink.

“IT WAS A CREATIVE WAY TO SUBDUE AN ENEMY! MY BABY BROTHER IS ABSOLUTELY BRILLIANT!” Papyrus had continued, not even acknowledging Sans’ arrival. “NOT QUITE AS BRILLIANT AS I AM, BUT WITH THE PROPER TRAINING HE COULD COME CLOSE!”

“DON’T BE A FUCKING IDIOT, PAPYRUS!” Undyne growled, still very well heard over the phone.

“WITH ALL DUE RESPECT, CAPTAIN, THERE IS A CHILD IN THE ROOM!”

“FUCK OFF, PAPYRUS! CALL ME WHEN YOU GROW A PAIR!”

Papyrus glared at the phone before making an annoyed “tch!” and a muttered swear under his breath before he threw the phone onto the counter.

“Rough day, Boss?” Sans asked, letting the baby grip his hand and shove his fingers into his mouth.

“UNDYNE CANNOT SEE THE BRILLIANCE OF MY TRAINING TECHNIQUES FOR BABY BLUE!” Papyrus declared, striking a pose. “BUT WE WILL SHOW HER!”

Blue had stopped chewing on Sans’ hand and frowned and started making his small fussing noises.

“Inside voice, bro,” Sans said.

“Shut up,” Papyrus growled, turning back to the pots he had on the stove.

“Sha sha bah BAH BAH!” Blue screeched.

“How come he doesn’t have to use his inside voice?!” Papyrus exclaimed.

“Because he doesn’t make us cry when he screams like a psychopath,” Sans said. “I have no problem leaving you with a crying babybones.”

“Fffff…. Shut up, Sans,” Papyrus grumbled, stopping himself from swearing.

Sans chuckled, gave Blue a gentle boop on the nose, and started getting the table set for their dinner.

“Heard somethin’ real funny today,” Sans said around a mouthful of lasagna.

“Oh my God, Sans, stop talking with your mouth full!” Papyrus said, throwing a napkin at Sans. “You’re setting a horrid example for Blue!”

Sans watched with some amusement as the napkin fluttered to the tabletop between them, the lightweight papery material barely making it halfway to him.

“I don’t think he needs _my_ help, there, Boss,” Sans said, jerking his head in the baby’s direction. “Seems like he ought to stop setting a bad example for me.”

Papyrus looked over and his eyes widened in near-horror.

After some debate, they decided to give Blue a piece of lasagna. Papyrus had cut it in tiny, manageable pieces, and served it to Blue on a plate along with a fork and napkin.

The napkin was nowhere to be seen – likely so doused in sauce and cheese that it was discernable from the rest of the mess that covered the high chair’s little table top. Blue’s face was covered in sauce, fingers sticky with ricotta and squashed pasta, his clothes has more of his dinner than anything else.

“BLUE! YOU ARE WASTING FOOD!” Papyrus exclaimed.

Blue didn’t seem to care about Papyrus’ raised voice this time, and instead giggled as he slammed his hands into the mushed mess and pushed the plate off and onto the floor.

“Oof, thank Asgore it’s plastic,” Sans said with a chuckle.

“He’s even worse than you!” Papyrus said, controlling his voice as he stood and loomed over Blue with a very displeased look. “Blue! This sort of mess in absolutely unacceptable! I demand you clean yourself up at once!”

Sans sighed pushing away from the table. “Boss, he’s gonna need a little help with that. The kid can’t even walk, can barely feed himself, hasn’t the whole idea and concept of a _baby_ gotten through that thick skull of yours yet?”

Papyrus crossed his arms with a huff. “Well, what do we do? I will not have such a mess in my kitchen!”

“We do what we do with any other mess,” Sans said with a sigh, unbuckling Blue from the high chair. “We clean it up.”

“What do you know about cleaning?!”

Sans leveled a very serious look at Papyrus as he picked Blue up, holding him close and not caring that he was getting the baby’s mess on his clothing.

“Papyrus,” Sans said seriously, almost flatly. “Look, I know it’s hard for you to believe, but I really did take care of you when you were Blue’s age. I know things weren’t perfect, and I know that I may not act like it as much as you want me to now, but I did take damn good care of you. I made sure you were clean, had clean clothes, and food to eat. I don’t expect a lot out of you in return, I was glad to do it, honored even, however, insinuating that I don’t know how to take care of a baby is really, _really_ insulting and I wish you would knock it off.”

Papyrus blinked, unable to look away from Sans until his older brother turned and went upstairs. Papyrus didn’t move until the sound of the water starting upstairs snapped him out of his stupor, and he moved to start cleaning the high chair and the floor around it.

* * *

Blue giggled and splashed the water. He had learned quickly to not be too enthusiastic, as the baby discovered he did not like water in his eye sockets.

Sans leaned on the edge of the tub, setting his head on the ledge, a small smile on his face as he watched the baby.

There was a light knock on the door, but Sans didn’t respond, even when the door was slowly opened. Papyrus came in and leaned against the vanity where the sink was, crossing his legs and his arms, and if Sans would have turned to look, he would have seen Papyrus staring at the floor and looking a little guilty.

“So, uhm,” Papyrus murmured. “You said earlier that you heard something funny toay?”

Sans inwardly sighed and his smile disappeared. “Yeah. There’s a rumor about town that Blue is our love child.”

Papyrus let out a small chuckle. “Seriously?”

“Seriously.”

“Who started that?”

“Dunno, Katherine didn’t have much info to give me.”

“Why is the world would anyone think that?”

“We don’t spend much time with anyone else, and we’re the only skeleton monsters anyone has seen, so, I guess it’s a logical conclusion.”

“I see.”

The only sounds for the next few moments were Blue as he splashed, giggled, and cooed.

“A’ight, lil monster, don’t want wrinkly bones, now do you?” Sans said, grabbing the towel and setting it across his lap just before reaching for Blue and lifting the squirming skeleton out of the water.

“Sans, bones don’t wrinkle,” Papyrus growled.

“Oh? Have you ever had wrinkly bones?”

“N-no, probably because you made sure I didn’t.”

There was silence, and Sans slowed his movements as he dried Blue off. Even Blue seemed to know something was going on, as he looked up into Sans’ face and over at Papyrus.

Finally, Papyrus sighed and moved to sit on the floor, pressing his back again Sans’.

“I’m sorry, Sans,” Papyrus murmured. “I don’t think you would lie to me about all the work you did when I was so… small. Now that we have Blue, I do see how much work you likely had to put in for me. I didn’t mean to hurt you.”

Sans finished drying Blue, wrapping the little skeleton in the damp towel before holding him close to his chest. Blue wriggled his arms free and reached up to pat Sans on the face.

“Pah pah pah pah,” Blue said quietly, his fingers gripping at Sans’ jaw.

“You’ve never apologized to me for anything,” Sans murmured.

Papyrus cleared his throat and shifted uncomfortably behind him. “I have to set a good example for Blue. As such, I apologize for any other time I should have apologized to you and have not.”

Sans looked down into Blue’s eyes, smiling, lifting a hand to trace around the sockets. He then leaned back more against Papyrus, dropping his hand to seek out his brother’s, gripping it firmly when he found it.

“Don’t sweat it, Boss,” Sans said. “Family means you love one another even when someone is being a jackass.”

“Nyeh, watch your mouth.”

“Sorry, Blue, sometimes you need to tell the absolute truth even if it means using naughty words.”

“You’re such a moron.”

Papyrus turned his hand over to squeeze his older brother’s hand.

Sans chuckled and squeezed his hand back.

* * *

Blue was dressed in the pair of pajamas that Sans was able to find for him – a cute little one piece made of soft, pale blue fabric with pale yellow sheep – and he was tucked into his crib.

“Okay, little guy, ready for “Peek a Boo with Fluffy Bunny?” Sans said, turning to the bookshelf.

“Here,” Papyrus interjected, handing Sans the book.

“Thanks, gonna stick around for Blue’s story time?” Sans asked. “Usually you’re down cleaning the kitchen.”

“It can wait this time,” Papyrus said.

“Whatever you say, buddy.”

Papyrus sat by the crib, peeking in at Blue through the bars. Blue made a small whining noise and reached out for Papyrus, who then smiled and stuck his finger in for Blue to grip onto.

Sans read the story, barely needing to see the words, even seeing Papyrus slightly mouth the words as they were read, his eyes never leaving the little baby in the crib. But the story did as it always did, not only did Blue’s eyes slowly shut as he eased into sleep, Papyrus did as well.

At the end of the story, Sans closed the book, putting it back in the bookshelf, and then gently bent to pick up his brother.

“Good thing we decided to put the crib in your room,” Sans murmured quietly. “Because there is no way I would have dragged your heavy ass from my room.”

“Language,” Papyrus murmured in his sleep.

Sans snorted. “Whatever, dude.”

He set Papyrus in his bed and covered him with the blanket. He paused a moment before bending down and pressing a quick kiss to his forehead.

“Love ya, baby bro,” Sans whispered.


	3. Baby Blue vs. Grillby

**Summary for the Chapter:**

> Grillby doesn't like kids.

_“Hey, Grill.”_

_“What is it, Sans?”_

_“Saw this chick in Hotland today, kinda looked like you.”_

_“Fuh, racist much, dick?”_

_“Hey now.”_

_“We’re not related!”_

_“A’ight, relax, didn’t mean nothing by it. Just wonderin’ if you have any kids wandering the Underground.”_

_“I fucking hate kids, Sans.”_

_Sans chuckled. “I’ll keep that in mind.”_

* * *

“YOU ARE NOT TO LET BLUE OUT OF YOUR SIGHT FOR A MOMENT!”

“I know, Boss.”

“I MEAN IT, SANS! AND YOU CANNOT SHIRK YOUR RESPONSIBILITIES!”

“What the- he’s a baby! You mean keepin’ a lookout for humans is more important?!”

“YOU CAN DO BOTH! KEEP AN EYE ON A BABY AND FOR A HUMAN! IN FACT, BLUE LIKELY COULD HELP YOU! AFTER ALL, HE HAS BEEN TRAINING WITH ME,” Papyrus struck a pose. “THE TERRIBLE PAPYRUS!”

Sans’ incredulous stare at his brother faded into one of amusement. He never could stay upset with Papyrus for long, even when he was being unreasonable, like the time he accused him of “napping all night.”

“A’ight, Boss, don’t worry so much. I raised you, and you know Blue’s safe with me,” Sans said, adopting a more serious tone.

Papyrus dropped his grandiose attitude and sighed. “I know,” he murmured. “I really wish Undyne would allow one of the mutts to go to the Capital today instead of me.”

He went over to the playpen that they had rigged for Blue. It was mismatched pieces of gate and latticework tied together with whatever they could find. At first glance, it probably looked dangerous to an outsider, but the brothers were diligent in making sure any sharp edges and ends were either cut or worn down as to not injure the baby - Sans had received another nasty gash to add to his collection up one arm during the building of said playpen.

“Better me than him,” Sans muttered, hissing through the pain and continuing working.

“Blue, as a senior member of the Royal Guard, Snowdin Division, I hereby issue you your first order,” Papyrus declared.

“I thought one had to be part of the Royal Guard in order to be, well, ordered?” Sans asked.

“For now, Blue is an Honorary Royal Guard Trainee,” Papyrus said.

“Haven’t heard of that rank.”

“That is because I have made it up especially for our dear little brother,” Papyrus said, pride twinkling in his eyes. “Actually, maybe this is something I can bring up during our meeting with the Royals. Blue is destined for greatness, I can feel it!”

“PAH!” Blue yelled, throwing a stuffed animal they found at Papyrus’ head.

Papyrus blinked, Sans cackled with laughter, which made Blue laugh. Papyrus turned to glare at Sans and took a deep breath as he turned back to Blue.

“Hmph. Despite your lack of respect to your higher up, Blue, I still shall assign you your first mission.”

‘ _I can’t believe he’s really going to do this,_ ’ Sans thought to himself.

Papyrus bent down and picked Blue up, holding him at arm’s length and regarding the baby with a very serious look.

“Blue, your first mission is to look after our older brother, Sans.”

Sans blinked. “Excuse me?”

“You are to be sure he doesn’t spend the entire day lazing about the house or nap the entire day away!”

“Boss, he has to take a nap, too.”

“ _He_ can nap, you will find something useful to do! Blue, you will also be sure he eats something other than mustard all day.”

Sans did his best to suppress his laughter.

“Do you understand your duties, Blue?”

Blue giggled and wriggled before making a grabbing motion at Papyrus. Papyrus grinned and pulled Blue in for the hug the baby asked for.

“You are so cute,” Papyrus whispered, so low that only Blue could hear.

“Ah bah bah bah bah,” Blue babbled, touching Papyrus’ face.

“I shall take that as an acceptance of your duties for the day,” Papyrus said, turning to drop Blue in Sans’ lap. “Well, brothers, I am off to the Capital! I should be home late this evening.”

“No worries, Boss, we got things handled here,” Sans said, putting his hands on Blue’s hips to steady him.

Papyrus’ weight shifted from one foot to the other. “I was sure to make extra lasagna for today, since I am certain that I would be home after the appropriate time for dinner. It’s in the food museum.”

“Okay, thanks, bro,” Sans said as Blue sprawled over Sans’ chest with a gurgle.

Papyrus still looked uneasy. “I also will have my phone, so, of course if you need me home for any reason, I can make it back as quickly as possible, I’m sure Undyne would understand if there was an emergency.”

Sans looked up at Papyrus. “Sure, Boss. We’ll be okay.”

Papyrus’ face twisted into an odd look.

“Pap?”

“I feel… funny.”

Sans stood, holding Blue close and moving to give Papyrus a hug with his free arm. “We’ll be all right, Boss, it’s just for a day. You can’t put your dreams on hold. If you miss this meeting, it could hurt your chances to be a captain like you want.”

“I, I know that!” Papyrus said, bristling for a moment and then calming down. “Just… are you sure you two will be all right?”

“Hey, I didn’t have a cool guy like you to leave us lasagna and a clean house to take care of a baby in,” Sans said, grinning up at his brother. “We’re good, I promise.”

“Okay,” Papyrus wrapped both Sans and Blue in a tight hug (so tight that Blue gave out a small squeak in protest) and then quickly made for the door. “I SHALL TAKE MY LEAVE BEFORE I CHANGE MY MIND! BLUE, MIND YOUR MISSION!”

“Bah bah bah!” Blue babbled.

“Be safe bro,” Sans said.

“NYEH HEH HEH, THE TERRIBLE PAPYRUS IS ALWAYS SAFE!” Papyrus said with a glint in his eye and a grin before he finally swept out the front door shutting it with a bit of a slam.

“Phew, thought he’d never leave,” Sans mumbled, going back to the couch and dropping back onto it with Blue sitting on his middle.

“Meh, meh, mweh heh heh!” Blue giggled.

“Oh, no, don’t you start that!” Sans said.

“Mweh! Mweh!”

Sans sighed.

* * *

The afternoon went as it usually did; After a quick call to the Dogi asking them to cover for his sentry shift for the day, Sans warmed up some lasagna for Blue along with a bottle, after cleaning them both up from the mess at lunch they fell asleep on the couch for naptime. Sans would have slept longer, but Blue woke up after an hour, as he always did, and woke Sans by crawling up to his face and poking and prodding, gripping and scratching at him.

“Okay, okay, you lil’ monster I’m up!” Sans said with a laugh.

“Mweh! Mweh!”

“You’re still hanging onto that, huh?”

“Ya.”

“Pfft. Okay, kiddo.”

They played, then Sans set Blue in the playpen for a bit so he could wash the high chair – Papyrus wouldn’t let him hear the end of it if he came home to find the chair covered in pasta sauce and cheese – and then he came back in to flop on the couch and turned on the television set.

“Great, another one of Metatton’s crappy reruns,” Sans grumbled.

Blue had crawled over to one side of the playpen and pulled himself up to his feet. He made a bunch off disapproving babbling sounds and rattled the gate.

“Yeah, I hear ya,” Sans said with a sigh, shutting the television off. “What’s say we get outta here for a bit, kid.”

Blue reached up when Sans came close to the playpen and promptly dropped onto his bottom, his arms still stretched up to be picked up.

“Heh, silly little baby bones,” Sans said, leaning over the gate to grab him. “Good thing we gave you some extra padding back there.”

Sans expertly put his jacket on while still holding Blue, who was also very good at gripping his legs around whoever was holding him, allowing them some more freedom.

“Hmm, kinda windy out there,” Sans murmured, looking out the door and then back at Blue. They didn’t have a coat for him. “Also, Grillby kinda has a no kids policy, but, you’re a baby, and he didn’t say anything about babies.”

Blue gave Sans a small scowl.

“What? Oh, come on, do you really want lasagna for lunch _and_ dinner, kid?”

Blue seemed to concede the point, but gripped onto Sans tighter.

“Hmm, I got an idea.”

* * *

“What’ll it be, Sans?” Grillby asked, somewhat distracted due to the chaos in the bar that evening.

“I’ll start with a plate of fries, you got your hands a bit full there,” Sans said with a wink. “But you’re on fire, tonight.”

“Ass,” Grillby huffed with a hint of amusement. “Give me a few minutes.”

Grillby shoved a bottle of mustard Sans’ way, who took it up with a grateful nod and began squirting the yellow condiment into his mouth.

“Buh bah bah!”

“Shh, kid, you’re gonna get us in trouble,” Sans murmured into the opening of his jacket. “Though, probably getting a little too warm in there for ya, huh?”

Sans unzipped his jacket a little more to make it more comfortable for Blue.

“There ya go, kid, and I’m getting’ ya some fries. Here, in the meantime, give this a try.”

Sans squirt a bit of mustard on his finger and offered it to Blue. Blue leaned forward, gripping Sans’ hand and shoving his mouth over the offered finger.

It was then that Sans remembered how much fun it was giving babies new kinds of food.

Blue’s face first screwed up into a sour expression. Sans had to drop the bottle of mustard and slap his free hand over his mouth to keep from laughing too loudly. Blue had released his finger, but then put it back in his mouth, making another sour expression before shoving Sans’ hand away.

“Guess that’s a bit strong to start,” Sans said with a huff of laughter.

“Sans.”

Sans startled and looked up to find the fire elemental inches from his face.

“Oh, heya, Grill,” Sans said coolly with his trademark grin.

“Is that a baby in your jacket, or are you just happy to see me?”

There was no amusement in that tone.

“Hey, come on, Grillz, you can’t say something like that so deadpanned.”

“Get it out.”

“Nah, come on, dude.”

“I don’t like children, Sans.”

“But he’s a baby!”

“And therefore, a child.”

“A baby is not a child, it’s a baby.”

As the two bickered back and forth, Blue wriggled until Sans’ jacket came more undone. Blue’s eyes were glued onto the purple elemental, fascinated by his flickering flames. When Grillby started accusing Sans of being a real pain in his ass that evening and emphasizing his point by putting a finger in the skeleton’s face, Blue reached up to grip the outstretched finger.

Grillby froze; of course, his flames wouldn’t ever hurt anyone unless he was focusing harmful intent, but few monsters took such liberties. Blue looked up at him and giggled as he pulled at his finger.

“If you fart, I’ll either laugh or kill you,” Sans said.

Grillby threw a glare at him. “Only you would be so classless, Sans.”

“Gah bah bah gah gah!” Blue babbled.

Grillby gingerly slipped his finger from the baby’s grip. “I’m so burning your next burger.”

Sans laughed as Grillby turned back to the kitchen. “You love me!”

Blue gurgled but then whimpered, snuggling into Sans.

“It’s okay, Blue, Grillby’s a good guy,” Sans said, rubbing the baby’s back through his jacket.

“Who’re you talkin’ to, Sansy?”

Sans sighed and rolled his eyes slightly. The drunk rabbit monster who was always in Grillby’s place cruising for a new boyfriend leaned against his side heavily.

“Ease off, Agnes,” Sans said, elbowing her away, albeit gently.

The monster peered into the open portion of Sans’ jacket. Blue stared up at her with his big blue eyes.

“Ish that a bay-baby?” she slurred.

“Uhm, yeah, he’s my baby bro.”

The rabbit blinked. “Bro? Isn’t that Papyrush?”

“Yeah.”

“Isn’t this you guys-es kid? Your love-child or summat?”

Sans shook his head. “No, he’s not our love child, the hell is wrong with you?”

“Lemme shee the shweetie-pie!”

The rabbit monster suddenly reached forward, and before she could lay a finger on Blue, he let out a screeching cry that made the entire bar go silent.

“Hey, hey, ish okay, baby,” Agnes cooed.

“Dude, get away from me!” Sans said, moving to shove the drunk rabbit away.

“Is there a problem here?”

They looked up to see Grillby looming over them with an annoyed expression, one hand on his hip while the other held a plate of French fries.

“I jusht wanted ta see the baby,” Agnes said. “He’s so cuuuuuutttee!”

Agnes reached over for Blue again, making him whine as he gripped tightly onto Sans, but she didn’t get far before a fiery hand gripped her wrist.

“Agnes, I think it’s time you went home and slept this evening off,” Grillby said calmly, almost soothingly.

“Aw, but Grillzy, the night’s jusht shtarting!”

Agnes jumped when a heavy paw landed on her shoulder. Sans looked up and gave Doggo a nod.

“C’mon, gorgeous, I’ll walk ya home,” Doggo said with a grin.

“Okay!” Agnes said, leaning heavily against the dog monster as he ushered her out.

“Well, someone’s getting laid tonight,” Sans said with a sigh.

Grillby just made a small grumbling noise in response and dropped the plate of fries in front of the skeletons. He also pulled up a bottle of ketchup.

“Mustard is probably not his thing yet,” Grillby grumbled. “Most kids love ketchup.”

“How would you know?”

“Shut up, Sans.”

“How much do I owe ya, pal?”

Grillby grunted. “That’s on the house. I can’t charge you when you’re trying to feed a baby.”

“Bah bah bah,” Blue said, smacking the bar with his hands.

Grillby stared down at the baby skeleton monster for a moment, then he made another grunting noise before returning to his duties.

“Huh, you might have won over one of the hardest asses in Snowdin,” Sans said with amusement as he took a fry and presented it to Blue.

Blue took the fry and began munching on it while Sans squirted a small mound of mustard on one side of the plate for himself.

It didn’t take long for the two skeletons to polish off the plate of fries. Sans’ jacket had since opened all the way and now Blue was sitting openly on his lap. Sans chatted with some of the other bar patrons, telling some jokes, making mentions of when he would be doing more comedy shows, but the fact that Grillby would pass them now and again and slip a few fries to the baby to munch on did not escape his notice. Sans made a mental note to torment the fire elemental about it later.

Blue was soon blinking rapidly, trying to stay awake, and as he failed he curled into Sans’ ribs and started to doze.

“Whoops, looks like it’s past the kid’s bedtime,” Sans said with a chuckle, rubbing the baby on the back before gathering him up a bit and wrapping his jacket firmly around the little body.

“Here.”

“Huh?”

Sans sputtered momentarily when a blanket was thrown over his head. He looked at the soft black material before looking up at Grillby, who was glaring at him with his arms crossed.

“You get that brat a proper jacket, Sans,” he growled.

“You saw what I had to go through to just get the damn bottles for him,” Sans said, wrapping the blanket around himself and Blue. “Thanks, pal.”

“Get home carefully,” Grillby said with a dismissive wave.

Sans said his goodbyes to the other patrons. Thankfully, the wind had died down, but it was still chilly as he trudged home, but the baby was warm against him and he hoped he felt just as warm in return.

* * *

Papyrus sighed in gratitude when he came into the front door of his home. It was a long day and he would be lying if he said he wasn’t a little distracted with concern over Sans and Blue. While he was a little annoyed to find the two curled up on the couch sleeping under a black blanket with the television blaring one of the late night MTT movies, he was also really glad to see them.

After carefully and quietly taking off his boots, jackets, and gloves, Papyrus went over to the couch and brushed the back of his hand down Blue’s cheek.

“I’m home, Blue,” he murmured quietly. “It looks like your first mission was a success. Congratulations, I am proud of you.”

“Mweh heh heh,” Blue murmured in his sleep.

“Nyeh heh heh,” Papyrus chuckled.

The slender skeleton reached for the remote and turned the television off before carefully wriggling his arms under Sans and picking both him and Blue up and bringing them upstairs to his room. He gently set Sans on the bed, then carefully picked up Blue to put him in the crib. He watched him sleep for a moment, still enchanted by how small he was, how peaceful, and Papyrus felt a swell of pride in the baby skeleton. He couldn’t help himself bending over in the crib to brush his teeth across the rounded forehead.

“Heh, you’re a fucking sap, Papyrus.”

“Shush, the baby is sleeping,” Papyrus said, straightening and turning to find his brother looking at him with sleepy eyes. “How long have you been awake?”

“Just saw you bending over the crib is all,” Sans said with a yawn. “Sorry for falling asleep on the couch, I’m sure that was an annoyance for you, especially after such a long day.”

Sans started to sit up.

“Where do you think you’re going?”

“To bed.”

“No, stay here,” Papyrus said, moving over to the closet to switch his battle body for his pajamas.

“You serious?”

“Why not?”

Sans shrugged, and moved over so Papyrus could climb into bed next to him.

“You okay?” Sans asked.

“Yes,” Papyrus said, closing his eyes. “I just missed you both today.”

Sans chuckled. “We missed you, too.”

Papyrus smiled, and then put an arm around Sans’ shoulders. Sans put an arm across Papyrus’ chest and soon dozed back off. Papyrus wasn’t far behind.

From then on, Sans, Papyrus, and Blue would sleep in the same room.


	4. Baby Blue's Day Out

**Summary for the Chapter:**

> Sans is sick, Papyrus takes Blue out on his errands.

“SANS! COME DOWNSTAIRS THIS INSTANT!”

“SAAAAAA! SA SA SA SAAAASS!” Blue yelled, trying to copy Papyrus.

Papyrus grumbled, moving to start up the stairs. “Stupid lazy good for nothing-!”

The door to their now-shared room opened and Sans stumbled out and looked over the ledge at his brothers.

“Saa! Saaa!” Blue cried with a giggle.

Papyrus’ face scrunched up (or as much as it did on a skeleton).

“SANS! WHA-!” Papyrus started, but then he paused, taking a better look at Sans.

The other skeleton didn’t look well; while their bones had a general shade of grey about them, Sans’ bones looked even more pale. The usual dark circles under his eyes seemed to be even darker, and while his anxiety often made him sweat, the amount and the fact that it was tinged by his magic were not good signs.

“’m up, Boss,” Sans muttered.

“Sans, you look awful.”

“It’s fine.”

Papyrus’ eyes narrowed. He went over to the playpen and put Blue inside, then he walked up the stairs to get a better look at his brother.

“Sans, you are very ill,” Papyrus said.

“Nah, I’m fine.”

“You’re full of shit.”

Sans giggled, leaning very heavily against the ledge. “Hey, no swearin’ in front o’ th’ kid.”

“Sans, you are sick and I order you to go back to bed.”

Sans blinked up at him. “But what about th’ human, Boss?”

“You are no good to me if you dust! Now get to bed!”

The amused look on Sans’ face faded. “You for real?”

Papyrus sighed, glancing over the ledge into the playpen to watch Blue pulling himself up on his feet and walking the perimeter, decided the baby would be fine for a minute or two, and immediately swept Sans into his arms.

“Hey!” Sans wriggled in protest for a moment, but then went limp with a groan.

“See? You are ill,” Papyrus said. “It’s likely just a bad cold, but again, you are of no use like this. You will stay in bed, I will check in as often as I can.”

“What about Blue?” Sans murmured, letting Papyrus set him on the bed and help him out of his jacket.

“He will just have to accompany me on my duties and errands,” Papyrus said, pushing Sans back and tucking the blanket around him. “If he stays here, he may catch your illness.”

Sans nodded. “Right, right, I definitely don’t want Blue to get this shit,” Sans made another pained face. “This sucks.”

Papyrus looked at Sans with a very concerned look. “What do you think it is, brother?”

“Well, like you said, hopefully it’s just a bad cold, nothing some rest, soup and such won’t take care of,” Sans said with a sigh. “But if it’s the skele-flu, then we might be in trouble.”

Papyrus shifted his weight from one foot to the other, not liking the sound of that and too worried now to ask for a further explanation. Considering Sans looked mostly asleep already, he didn’t want to trouble him too much, either.

“Should I stay home?” Papyrus asked.

“Nah, let me sleep, I’ll be okay,” Sans murmured.

Papyrus nodded tightly. “All right, brother, if you insist.”

He bent with the intention to drop a kiss on Sans’ forehead, but the sweat reminded him that Sans could be contagious, and he needed his cool brother to take care of him, therefore Papyrus couldn’t afford to get sick. Instead, he caressed the sweat-covered skull and quietly left the room.

Once Papyrus was downstairs, he washed his hands, then he went to get Blue out of the playpen.

“BLUE! TODAY I WIL GIVE YOU YOUR SECOND MISSION!” Papyrus declared, holding the baby at arms’ length again.

Blue did his usual gurgle and giggle, but then seemed to sober himself when Papyrus continued to look him in the eyes.

“BLUE! YOUR MISSION TODAY WILL BE TO ACCOMPANY ME ON MY OWN MISSIONS FOR THE DAY! YOU WILL TRULY LEARN WHAT IT TAKES TO BE IN THE ROYAL GUARD!”

“Ah bah bah bah,” Blue babbled.

“EXCELLENT! NYEH HEH HEH!”

“Mweh heh heh!”

Papyrus chuckled and pulled the baby close, curving an arm under his bottom to hold him close and secure as he went to where his scarf was hanging as well as another long piece of black fabric.

It wasn’t the blanket that Grillby had given to Sans a few days ago, but something that Sans had brought back when they were scrambling for items to take care of Blue. Apparently, this was something that the rabbit at the shop had given to Sans, explaining that it was invaluable as it was a way of carrying the baby but keeping your hands free. While at first Papyrus felt that this was ridiculous and a way for Sans to be lazy, now that he had no choice but to keep Blue with him for the day, he was reconsidering his stance on the invention.

Papyrus sighed, glancing at the black fabric and then looking at Blue.

“I apologize Blue, but, I have no choice,” Papyrus said.

However, after some time, Papyrus got frustrated trying to figure out how to wrap the fabric to keep Blue secure. Blue didn’t seem very happy with the process either, finally fussing to the point of crying before Papyrus set him down on the floor, almost ready to join the baby in an identical show of frustration.

Papyrus got Blue a bottle to help calm him down, not wanting to wake Sans and cause him any worry or stress; he was The Great and Terrible Papyrus! He could figure this out!

However, only one solution came to Papyrus’ mind and he really wasn’t too happy about it. Finally, as he took in a deep breath and was renewed with resolve, he scooped up Blue, deposited the now-empty bottle in the sink, grabbed the black fabric and headed out the door.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

Katherine blinked at Papyrus. “You have got to be kidding me right now.”

“THE GREAT AND TERRIBLE PAPYRUS DOES NOT KID!”

The bunny stared at him. “You, Papyrus, are coming to me for help?”

“YES! YOU WERE THE ONE WHO SOLD THIS TRASH TO SANS, AND YOU WILL TEACH ME HOW TO USE IT!”

The bunny monster continued to stare at Papyrus, before amusement finally seeped into her chocolate brown eyes and a gentle laugh escaped from her fuzzy mouth.

“Ha, ha, oh, Papyrus, it’s just I never imagined- you know what? Never mind, you have duties to get to, I get it,” Katherine said, coming around the counter. “And for the record? I didn’t sell this to Sans. I gave it to him. I felt a little bad since I saw you boys struggling to get all the crap together to take care of your little hell spawn.”

“BLUE IS NOT HELL SPAWN!”

Katherine looked up at Papyrus a little dubiously, and then down at Blue, who blinked his big blue eyes at her for a moment, then cooed and giggled. She couldn’t help smiling.

“With eyes like that? Maybe not,” Katherine murmured. She shook her head. “Anyways, let me give you a couple of lessons on how to carry your little lovechild.”

“OH MY GOD HE’S NOT MINE AND SANS’ LOVECHILD!”

Katherine snickered as she took the fabric and started straightening it out.

Papyrus glowered at her. “If my baby brother were not present, there is a word I would like to use to describe you.”

“Do you want to learn how to wrap this or not?”

“Nyeh. Proceed.”

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

It didn’t take as long as either of the adult monsters thought it would; Papyrus was shocked to learn that Katherine was a surprisingly good instructor, and Katherine was, in turn, surprised by how quickly the skeleton monster could learn, and Blue happily cooed and gurgled through the entire affair.

“It doesn’t even look half bad,” Katherine said, stepping back and looking Papyrus up and down. Blue was seated facing forward in the material wrapped around him and Papyrus’ shoulders and waist. “I mean, it does take a bit of the intimidation factor away, what little of it you had.”

“Shut up, rabbit.”

“Oooh, that one hurt.”

“Would you prefer hasenpfeffer?”

Katherine wrinkled her nose. “Oh, get the hell out of here, you upstart.”

“Ba ba ba ba ba!” Blue babbled, waving his arms at Katherine.

The anger vanished immediately and she bent down to press her twitching nose to the pure white cheekbone.

“And you, cutie pie, give Papyrus as much trouble as you please,” she said.

Papyrus rolled his eyes.

“Mweh heh heh!” Blue giggled in reply.

“Oh, sweet Asgore, not you, too,” Katherine said.

“Nyeh, heh, heh, come Blue, it is time we check in with the Pack,” Papyrus said, turning to leave.

Katherine shook her head and went to sit in her usual spot behind her counter.

“Oh, uhm, Katherine?”

“What is it, Papyrus?”

Katherine was a little surprised to see a slight blush on the skeleton’s cheeks; mostly because she didn’t know skeletons could blush, and also because Papyrus didn’t seem the type.

“Thank you,” the tall skeleton murmured before rushing out the door and all but slamming it behind him.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

Papyrus ignored the funny looks he got from the villagers; he still strode proudly towards the sentry stations of the member of the Dog Pack so he could fulfill the first duty of his day. As he neared Doggo’s station, he was irritated to see him smoking a dog treat and chatting with Lesser Dog, but he was glad because that meant one less station for him to check.

“Hey Boss,” Doggo said with a half-wave.

“DOGGO! HOW MANY TIMES MUST I TELL YOU THAT CAPTAIN UNDYNE DOES NOT TOLERATE SMOKING WHILE ON DUTY!” Papyrus growled.

Doggo rolled his eyes and tossed the smoking treat into a nearby pile of yellow snow. Lesser Dog looked excited and started stretching its neck towards it.

“STAY!” Papyrus ordered.

Lesser Dog whined, but obeyed.

“Sta sta sta!” Blue babbled.

Doggo blinked. “Is that yer kid?”

Lesser Dog’s attention was immediately grabbed and he quickly closed the distance between him and Papyrus as he excitedly started sniffing the baby.

“HE IS NOT MINE AND SANS’ CHILD, AND STAY AWAY FROM HIM YOU MANGY CANINE!”

Doggo laughed and Papyrus went to push Lesser away when Blue giggled at the attention.

“Wa wa wa!” Blue said, reaching out to pat Lesser on the snout.

Papyrus looked irritated, but he cleared his throat. “Well, seeing as Blue seems to like you, I shall allow it,” he glared down at the dog. “But you keep those teeth in or else.”

“Puppy!” Lesser barked and continued to sniff at Blue as if he was never given a dire warning.

“Wiggly,” Doggo murmured, reaching in his back pocket for another treat. “Good, can keep a proper eye on the thing.”

“DON’T YOU DARE LIGHT THAT, AND DO NOT CALL BLUE A ‘THING!’” Papyrus demanded.

“Sure, Boss,” Doggo said with a shrug, sticking the treat in his mouth.

“Puppy!” Lesser Dog barked again, nuzzling Blue’s neck and making the baby squeal in delight.

“REPORT, DOGGO!” Papyrus ordered.

“Same as always; no signs of a human, nothing odd going on in and around town, puzzles are still activated and no traps have been triggered,” Doggo said, counting off each point with a fuzzy finger.

“ALL RIGHT. ANYTHING ELSE OF NOTE TO REPORT?”

“If there was, I woulda told ya.”

“VERY WELL, THEN! SANS WILL NOT BE AT HIS POST TODAY AND PERHAPS TOMORROW. I EXPECT THE REST OF YOU MUTTS TO PICK UP HIS SLACK!”

Doggo groaned.

“DON’T GIVE ME THAT! I AM GOING TO GO CHECK ON THE DOGI AND GREATER DOG.”

“A’ight.”

“LESSER DOG! DO NOT SLOBBER ON BLUE!”

The other dog backed off and whimpered.

“Puppy? Pup puppers?” Lesser Dog whined with a small bark.

“IF YOU MEAN BABY, YES, BLUE IS A BABY; HE IS MY BABY BROTHER AND YOU WILL SHOW HIM THE SAME RESPECT YOU ALL SHOW ME!”

“Oh, so, none at all?” Doggo quipped with a grin.

Papyrus shot a glare at him.

“Hey, whoa, take it easy, Boss, I’m kidding,” Doggo said, holding his hands up placatingly.

Papyrus smirked. “KEEP UP YOUR DUTIES, BOTH OF YOU.”

Lesser Dog straightened and saluted. Doggo gave Papyrus a half-hearted salute, slouching and leaning against the side of his station.

“You got it, Boss,” Doggo said.

“EXCELLENT.”

Papyrus turned on his heel and started off for the Dogi’s station. Lesser Dog whined.

“Puppy? Puppy pup pup pupupupupup,” he babbled.

“Yeah, that’s the new pup,” Doggo said with a tolerant sigh.

Lesser Dog nodded and suddenly got a very serious look. “Protect the new pup.”

Doggo scoffed as he lit the treat in his mouth. “Sure, protect the new pup.”

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

After Papyrus checked in with the others, each of the dogs taking their turns to sniff the baby skeleton, declaring him the New Pup and agreeing that he would be protected the same as the “Older Pup” (Sans), Papyrus was glad to be away from the canines’ baby frenzy.

“Honestly, you would think they have never seen a baby monster before,” the tall skeleton muttered, wrapping his arms around Blue and hugging him firmly to his chest.

“Woof!” Blue shouted.

“Nyeh, don’t pick up such bad habits.”

“Mweh heh heh!”

Papyrus sighed, looking around the town, wondering if he should go back to the house to heck on Sans before continuing when a vibration in his pocket nearly startled him. He pulled out his phone.

“Oh for f-!” he started to swear but Blue was looking up at him. “French fries,” he covered slowly, shoving the phone back into his pocket. “I nearly forgot that Undyne and I had a training session!”

Papyrus frowned down at Blue. This was a highly advanced training session that he and Undyne did together. He was concerned about Blue’s safety. After a moment, however, Papyrus had made up his mind.

“BLUE! YOU SHALL ACCOMPANY ME TO MY TRAINING SESSION AS WELL!” Papyrus declared. “THIS MAY BE THE PERFECT OPPORTUNITY TO SHOW UNDYNE THAT I, TOO, CAN BE A GREAT TRAINER, AND SHE CAN SEE WHAT EXCELLENT SKILLS YOU ALREADY POSESS! BEING THE BABY BROTHER OF THE GREAT AND TERRIBLE PAPYRUS HAS ITS PERKS! WE CAN SHOW UNDYNE THAT YOU WILL BE MORE THAN FIT TO TAKE PART IN THE ROYAL GUARD! NYEH HEH HEH HEH HEH!”

“Mweh heh heh!” Blue giggled.

Papyrus grinned, pat Blue on the head, and started heading for Waterfall.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

“Hey Papyrus! Thought you weren’t going to show! I was just about to-!”

Undyne had opened her front door, and she stopped dead when she locked her one good eye on the big bright orbs staring at her from Papyrus’ chest.

“HELLO UNDYNE! I BROUGHT MY BABY BROTHER, BLUE, WITH ME TO ALSO TAKE PART IN OUR EXTRA SPECIAL ONE ON ONE TRAINING!” Papyrus said.

Undyne looked at the baby, then up at Papyrus. She pursed her lips into two very, very thin lines before gritting her sharp teeth.

“Why… don’t… you two… come… in…” she ground out.

Papyrus glanced down at Blue with an encouraging wink and followed Undyne into her kitchen, shutting the door behind him.

“Look, Papyrus, I know you’re excited about you and Sans finally having a kid and all,” Undyne started.

“OH MY GOD! HE IS NOT OUR LOVE CHILD!” Papyrus shouted.

“Easy, easy,” Undyne said. “I wasn’t sure, so…”

“SO YOU TURN TO RUMORS?!”

Undyne snickered. “Ease up, Papyrus. Man, I knew you had a stick up your ass but, sheesh.”

Papyrus covered Blue’s ears and gave Undyne a pointed look; he felt like he was already pushing his luck a bit being so casual, and he knew bringing Blue was going to be a point of contention, but there were still some things one just did not do around such a young child!

Undyne looked down at Blue, who was still staring at her, and then back up at Papyrus.

“You know he’s going to hear a hell of a lot worse by the time he’s two, right?”

“That doesn’t mean I can’t try to give him a better life!” Papyrus sniffed.

Undyne laughed. “Oh, man, you really are taking this baby thing to a whole new level, Papyrus. All right, all right, you want the kid to train so badly? Then he’s gonna train!”

Undyne suddenly leapt onto her table. She balled up one fist, holding it to her chest briefly before looking up, a spark in her eye before she pointed dramatically at the two skeletons.

“YOU MAY REGRET THIS ONE DAY, BABY BLUE,” Undyne shouted. “BUT IF YOU REALLY WANT TO BE IN THE ROYAL GUARD, THEN YOU WILL SHOW ME YOUR GUTS, SHOW ME YOUR HEART, SHOW ME WHAT YOU’RE MADE OF!”

“Undyne, we’re skeletons,” Papyrus reminded her flatly.

“THEN YOU WILL SHOW ME WHATEVER IT IS YOU SKELETONS HAVE INSTEAD OF GUTS!”

Undyne jumped off her table and stood by her stove, banging a fist on the counter and stomping on the ground until a pot and a basket of vegetables fell onto the counter.

“Papyrus! You have shown me that you can bash vegetables with all of your might! You are now ready to learn how to cook…”

Undyne paused for dramatic effect, Papyrus was looking at her with widened eyes and bated breath. Blue was looking between the two as if they had lost their minds.

“NOODLES!” Undyne shouted, pounding her fist on the counter again, making a box of lasagna noodles drop beside the stove. “AND YOU, BLUE, NOW YOU WILL SHOW ME WHAT YOU CAN DO WITH VEGETABLES!”

The two of them stood unmoving for a moment, Papyrus looking down at Blue and Undyne glancing between the ingredients and her students.

“Erm, well, I can’t in good conscience have you cooking on the stove with a baby between you and it,” Undyne muttered. “What do we do with him?”

Papyrus started to worry; maybe bringing Blue was not the best idea, but what choice did he have? Sans was sick! But he wished he would have thought to bring the play pen… though it took a long time to set up…

“I, uh, I guess I’ll hold the kid?” Undyne murmured, though sounding the most unsure Papyrus had ever heard her.

“I suppose?” Papyrus said with a shrug.

Blue giggled as Papyrus pulled him out of the wrap, but his giggling stopped as he went to hand him to Undyne.

Blue screamed and turned to grip whatever part of Papyrus he could.

“Now, Blue, it’s all right, you can trust Undyne,” Papyrus said soothingly.

“Yeah, c’mon kid, you can trust me,” Undyne said with a wide grin and open arms.

But Blue wasn’t having it. His screams turned to crying and he buried his face between the wrap and Papyrus’ scarf. Papyrus had quickly started rocking Blue and making soothing, shushing sounds. Undyne looked very cross, like she had been insulted.

“Maybe we can just set him on the floor?” Papyrus suggested.

“I guess,” Undyne said with a sniff. “It would probably be safest to put him closer to the piano; I don’t want him near my fridge or my awesome sword.”

Papyrus nodded and set Blue down on the floor. He sat up on his knees and put his fists on his hips.

“BLUE!” he declared, grabbing the baby’s attention. “YOU SHALL REMAIN OVER HERE WHERE YOU WILL BE SAFE! YOU WILL ALLOW UNDYNE TO GIVE YOU VEGETABLES AND YOU WILL SHOW HER THAT YOU TRULY ARE THE FUTURE CAPTAIN OF THE ROYAL GUARD!”

“Mweh! Mweh!” Blue giggled.

“What the hell is that?” Undyne asked with a snort.

“I believe he is trying to imitate my frightening cackle,” Papyrus said, standing up. “Undyne, I believe now that I have given Blue his assignment, he shall follow it. By all means, proceed.”

Undyne gave Papyrus an odd look, glanced at the baby, then shrugged before taking up an onion, some garlic, and a few tomatoes and setting them in front of Blue, who recoiled back slightly with a whimper.

“Relax kid,” Undyne sighed before standing and crossing her arms and looking sternly down at the baby before clearing her throat and switching her attitude back to her training mode. “Now, Blue! You’re going to show me what your made of! Bash those veggies! I will be back to check your progress while I teach this nerd how to make noodles!”

Blue looked curiously at the veggies, lifting each one up in turn and promptly putting them in his mouth. He made faces with the onion and the garlic, but he sucked on a tomato until he got a mouthful of seeds. Slightly disgusted, he spat them out, and in a moment of frustration, he slammed the tomato on the ground. It smashed, of course, more juice and seeds squirting onto the linoleum. He tried the same with the onion, and found that if that vegetable was going to smash, he had to slam it harder into the ground. The garlic he had the least success with, but the cloves fell apart.

After some time, his high-pitched giggles and shrieks of joy drew the attention of the adult monsters and they turned to look at him. Undyne and Papyrus both watched Blue as he happily pounded the tomatoes into the mush of onion that he created. He gurgled, grinning up at the other two as he gripped the remains and squeezed them between his little bony fingers.

“FUHUHUHU! Papyrus! I think I like the kid!” Undyne cackled, smacking the skeleton heartily on the back.

Papyrus could only give Blue a very rare grin, careful to not let Undyne see it.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

Sans woke up in the dark. He blinked, a little dazed when he realized he had slept for the entire day.

“At least I’m feeling better,” he murmured, sitting up slowly and stretching his back.

A familiar scent tickled his nose, and as his eyes adjusted to the dark, he noticed that there was a bowl on the small table next to the bed. It was chicken broth; Papyrus had been in to check on him. Sans smiled, taking a sip of the broth from the bowl to soothe the bit of dryness he felt within him, and he slowly stood up and made for the door.

He really was feeling better; none of the other symptoms he had before were present and he was certain that the majority of the danger had passed. Sans was even certain that he was no longer contagious.

Sans’ eyes were met with soft light coming from the television downstairs. He looked over the side and he smiled at the sight that greeted him.

Papyrus was laying on the couch, still completely dressed, one leg hanging off the edge of the cushions, and both arms wrapped over the baby skeleton sleeping on his chest. Blue looked happy, smiling in his sleep.

Sans came down the stairs. When he got closer, he noticed that Blue still had some dried tomato seeds stuck to the side of his little skull. Sans brushed them away with a chuckle.

“Guess you got to see Undyne, huh, kid?” Sans murmured, bending to drop a small kiss on the baby’s head. “Hope the ol’ fish wasn’t too rough on ya.”

He looked up into Papyrus’ face; it was still a bit of a guarded look, but quiet. Sans smiled and passed his hand over his forehead.

“Thanks for being such a cool bro,” Sans murmured, leaning in to drop a kiss on his head as well before turning to the kitchen to search for some mustard.

“Sans?”

He turned to the soft, sleepy murmur.

“Hey, how did your day go?”

“How are you feeling?”

“I’m fine.”

“The day went well.”

“Good. It’s late, Pap, want me to take Blue to bed?”

Papyrus looked down at the sleeping baby. “I’d hate to wake him, and you may still be sick.”

“Nah, I’m all right. You sure you wanna sleep on the couch?”

“Yes.”

Sans smiled, turning back to grab the blanket hanging on the other edge of the couch and covered the two, tucking the blanket a bit around the baby.

“Sweet dreams, bros.”

“Love you, Sans,” Papyrus murmured as he drifted back to sleep.

Sans stood stock still; Papyrus hadn’t said such a thing since he was very young. It made his soul ache and burst at the same time. He smiled.

“Love you, too, Papyrus.”


	5. Baby Blue and Swap, Too!

**Summary for the Chapter:**

> Another arrival in Underfell creates some chaos.

It had been about a month since Blue had come into the lives of the skeleton brothers and neither remembered the last time they saw their brother so happy. Sans was reveling in taking care of a baby again; he didn’t realize how much he missed Papyrus as a baby, and though back then it was a very tough life for them, now being older and wiser made the difficult parts easier and the easier parts even more enjoyable. Papyrus also felt a certain bit of joy and pride having a baby brother; he found a bit of a niche in training Blue, and while he didn’t always seem to get the results he expected (Blue would still subdue his “enemies” via hugging and giggling), Papyrus was still proud of the little skeleton’s progress.

“I think he’s going to be walking soon,” Sans said, sitting in front of his sentry station, holding an arm out for Blue to grip onto as he pulled himself up on his feet.

“He better!” Papyrus said, crossing his arms. “He must be able to walk if he is going to further his training!”

“Mweh heh heh!” Blue giggled triumphantly as he got to his feet, but then plopped back in the snow as soon as he had let go of Sans’ arm. His face scrunched up in frustration as Sans laughed.

“Guess he’s not going to _stand_ for that,” Sans quipped.

“SANS!” Papyrus exclaimed.

“SA!” Blue added, glaring up at him.

Sans continued to laugh. “C’mon kid, you know I’m always happy to give you a _leg_ up.”

“OH MY GOD!”

Blue scowled.

Sans fell to his side, laughing more because of the looks Blue was giving him.

“Lemme guess; one more pun, and you’ll _walk!_ Bwahahah- gah!”

“Mweh.”

Now it was Papyrus’ turn to laugh; Blue had thrown a handful of snow at Sans and it landed directly in his eye socket. It was a small handful, but that was more than enough to make the shorter skeleton sputter and sit up, clawing at his empty eye socket.

“SERVES YOU RIGHT!” Papyrus declared, bending down to scoop up Blue and nuzzle the side of his face. “I AM QUITE PROUD OF YOU, BABY BROTHER!”

“Yeah, yeah,” Sans muttered, sitting back up and then shooting a more malicious grin at the other two. “ _Ice_ -ee how it is now. It’s _snow_ problem, though, I’ll just go with the _flow_.”

Papyrus and Blue were both about to let loose a cry of frustration when they were interrupted by a cry that made them all freeze in place.

It was long and loud, a mix of fear and pain. Sans’ eye lights blanked out, afraid of what it meant, and he started readying himself for a fight.

“You two stay here,” Sans muttered, pushing past them.

“Sans, wha-?”

“Just stay here with Blue, okay?” Sans snapped. “If I don’t come back in five minutes, go home.”

Papyrus was about to protest, but Sans’ tone along with Blue’s hands curling into his scarf and letting out a small whimper of worry kept him still as he realized that Blue needed someone to protect him.

Sans ran off.

“He better be careful,” Papyrus muttered.

Blue whined.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

Another cry rang up from the trees, spurring Sans to move faster towards the sound; on one hand, the second cry was a good sign as it gave him confirmation of the direction, on the other hand, it could be an indicator that he was going to be too late.

He came to a clearing where the cry had seemed to dissolve into sniffling. Curious, now, he was slower, more careful, and he moved between and behind the trees. In the center of the clearing, there was a mound, covered with a dusting of snow (oh, stars, Sans hoped it was snow), shuddering, and apparently the source of the cry.

“Hey!” Sans barked.

The mound jumped and spun around, and what faced Sans made him immediately drop his gruff demeanor.

Nestled into the large, dark orange hoodie was a skeleton’s face. A bony hand reached out towards him suddenly from a sleeve, orange magic glowing from one eye socket, and suddenly a small wave of orange bones rushed at him.

“Holy sh-!” Sans cried, almost reacting too slowly to move forward through the attack.

“Stay away!” the other skeleton cried, voice cracking and shaking.

Another wave of orange bones rushed at Sans and he easily moved forward through them, quickly closing the distance between him and the other monster, and soon enough, he was towering over the other.

“N-no! S-st-stay b-!” the other got up on its knees and went to shove at Sans, but a pained cry made it recoil, curling into itself with a sob.

“Take it easy,” Sans said. “You’re all right.”

But when he kneeled down, he saw the other sleeve was soaked with what seemed to be marrow and magic.

“Or… not?”

“P-please,” the whisper came from deep inside the sweater. “M-mercy, please.”

The other monster crumpled, dropping into the snow, and laying very, very still.

“Hey,” Sans gently touched what he assumed was a shoulder. “You okay?”

He pushed the hood back and nearly choked at the face that was underneath it; not only was it most definitely another skeleton, but it was a young child - four, maybe five years old - and save for the flatter teeth, they looked just like Papyrus.

“What the fuck?” Sans murmured. “What the hell is a kid like you doing out here like this? And with that face, no less.”

Sans decided it was something to figure out later. He was very careful and gentle as he manipulated the child into a laying position. He tried his best to assess what was wrong with their arm, his best guess was that it was broken, which meant he definitely needed to get the child home.

“Don’t worry, kid,” Sans said, scooping the monster into his arms. “I gotcha, don’t worry.”

His soul fluttered when the child unconsciously turned their face into his jacket, immediately instilling a sense of protectiveness as he started walking back to his station.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

It had been a while, and Papyrus was about to start for home like Sans had instructed, but thankfully, his brother was soon coming out of the woods with something in his arms.

“SANS, WHAT IN THE WORLD-?”

“I don’t know,” Sans said with a sigh as he came closer. “They were by themselves and they’re hurt pretty badly.”

Blue turned in Papyrus’ arms and his big blue eyes widened at the child in Sans’ arms and began squealing, waving his arms excitedly.

“BLUE, CALM YOURSELF!” Papyrus cried, not sure how to handle to suddenly squirming baby.

Blue immediately began to cry when he realized he wasn’t getting what he wanted. Sans sighed.

“Let’s get them back to the house,” Sans said.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

Sans sat by the couch, watching the unconscious child. He got them out of the wet clothing they were in and into one of Sans’ old shirts. It was far too big on the little monster, but it would do. Thankfully, the little one’s arm wasn’t broken, only fractured and very aggravated, which lead to the loss of marrow and magic that likely caused the child’s fainting. A bandage and some healing magic would assure that no scars would be left behind.

Blue would pitch a fit if he weren’t in the same room as them all, so Papyrus kept him busy sitting on the floor of their living room, playing with various toys.

“Do you think Blue knows this child?” Papyrus asked.

“A safe bet,” Sans sighed. “Or he thinks they’ll disappear if we separate them. Who knows?”

Silence continued to fill the room, until finally, a small groan came from the small skeleton as their eyes blinked open.

“Hey, kid,” Sans said softly, not wanting the startle the little one.

Immediately, their eyes blew wide in panic. “N-no, stay away!”

The child went to move but the pain in their arm stayed them.

“Take it easy, bucko,” Sans said. “You’re safe here, okay?”

The child looked up at Sans fearfully, then glanced down at Papyrus, and looked back up at Sans.

“W-why are your teeth all pointy?” the child asked.

“Helps me chew my food,” Sans said with a wink.

The child looked a little reproachful. “Only bad monsters have pointy teeth.”

Sans chuckled. “Well, I brought you home, got you warm, and healed your arm; I must be the worst bad monster there is.”

The child considered this for a moment before nodding. “Yeah, a bad monster would have eaten me, unless you’re saving me or something.”

Sans snorted. “But you’re nothin’ but bones, kid.”

Papyrus grumbled.

The child gave a small laugh.

“ _Tibia_ honest, though, you’re a little on the small side for a big-boned guy like me.”

The child continued to laugh while Papyrus and Blue were both making sounds of disapproval.

“My bro doesn’t find eating kids very _humerus_ either.”

“ENOUGH!” Papyrus shouted.

“BA BA BA!” Blue agreed.

At first the child recoiled, but then perked at the sound of Blue’s voice.

“Sans?” the child asked.

“Yeah?” Sans answered.

“No! My brother! You have my brother!”

The child began to shove off the blankets, ignored the burning pain of their injured arm when Sans pushed them back down firmly.

“Kid, take it easy,” Sans warned.

“No! Let me go! I want my brother! Give me my brother!”

The child began to cry. Blue seemed to recognize the child’s voice as well and began to fuss. Papyrus quickly picked Blue up and turned to face the young skeleton.

“OH MY STARS, SANS!” the child sobbed, reaching out for the baby.

“PAH PA PA PAH PAH!” Blue said excitedly, also reaching for the other.

With barely a glance between them, Sans and Papyrus helped support the reunion of the two little skeletons, the baby giggling and touching any part of the little skeleton he could while the other broke out into fresh tears.

“I thought I would never find you! I looked everywhere! Then I fell and I was stuck in the woods and it was cold and-!”

The child continued to babble between sobs, squeezing the baby skeleton as they spoke, and slowly Blue seemed to be less and less happy with his situation.

“Blue is your brother?” Papyrus asked. “But, didn’t you call him Sans?”

“His name _is_ Sans,” the child insisted.

“Huh. That’s funny, cause that’s my name,” Sans said. “We’ve been calling him Blue.”

“Funny, that’s what I call him sometimes,” the child said, wiping away the tears with their good arm while awkwardly holding onto Blue with the other.

“What is your name, then?” Papyrus asked.

“Papyrus.”

The adult skeletons exchanged a look.

“Y-your name is Papyrus too, huh?”

They looked back at the child.

“Yes, it is,” Papyrus said.

“I guess I better get a nickname then, too! No fair that my brother has one!”

“I, I guess so,” Sans stammered, his mind now reeling with this new information. “Since, uh, you can talk and such, you wanna pick out your own?”

The little Papyrus nodded, letting Blue chew on his hand as he idly traced a finger over the top of the baby’s skull. They waited patiently while he thought.

“We sorta swapped, didn’t we?” they murmured thoughtfully after a while. “Swap sounds like a neat nickname.”

Sans smiled. “A’ight then, Swap.”

“Are you a girl or boy?” Papyrus asked.

Sans shot him a look, but then again, he remembered, that Papyrus hadn’t seen many children before.

“I’m a boy,” Swap answered, not bothered by the question at all. “I don’t mind if someone calls me a ‘she’ but it seems silly. Blue doesn’t like it, though.”

Blue made a mumbling sound and leaned back into his brother, still holding and chewing his hand. Swap yawned and snuggled back into the couch.

“Is it nap time?” he asked.

“Yeah, kid, it’s nap time,” Sans said, patting him on the head. “Don’t worry, pal, we got you and your bro. No need to worry about anything.”

Swap looked up with tired eyes, and Sans suddenly realized how tired the kid looked, as if he had lived ten lifetimes; it reminded Sans of himself enough to make him shudder.

“I do not think they both would be safe on the couch like that, brother,” Papyrus muttered.

“Nah, they’ll be fine, they’re both so little,” Sans said.

Swap was already mostly asleep, and he had moved onto his side, curving his arms protectively around the baby who also snuggled in for a rare nap.

“Let’s go into the kitchen,” Sans whispered.

Papyrus nodded and followed his older brother into the next room, glancing back at the monster children asleep on the couch, part of him worried about their safety, but he quelled that worry as Sans motioned for him to sit down and they began to have a very long talk.

Sans explained as much as he could; while Papyrus was not stupid by any means, he never had much of a mind for science. Even then, there didn’t seem to be a particular answer to how exactly Blue and Swap ended up their world. It didn’t take the skeleton brothers long to figure that all in all, it really didn’t matter.

“If they do come from some wacked out mirror dimension, it’s likely they would have been on their own, like we were,” Sans said. “Swap is pretty brave, and probably very capable.”

“I WILL NOT HAVE IT!” Papyrus declared. “THEY ARE OUR BROTHERS NOW, AND OUR RESPONSIBILITY!”

“Okay, Boss,” Sans said with a chuckle. “Though if the rumors were bad before, wonder what they’re all going to say now.

Papyrus’ face turned very sour at the prospect, but let it go. He cleared his throat and stood up.

“I SHALL START COOKING OUR DINNER! SWAP NEEDS A NUTRITIOUS MEAL TO HELP HIM HEAL FROM HIS INJURY!”

“Heh, hope he likes lasagna,” Sans grinned. “It should help him put the _pasta_ in the _pasta_.”

“YOU CAN FEND FOR YOURSELF!”

“I’m gonna go check on them,” Sans said, pushing away from the table. “Make sure the kid doesn’t have Blue in an awkward position with that arm.”

Sans stopped in the doorway and feel very quiet. Papyrus looked over, pausing in taking a pot from the cabinet.

“SANS?”

“The kids are gone.”

“WHAT?!”

The pot clattered to the floor as Papyrus rushed to the doorway, nearly knocking Sans forward to gaze on the empty couch with the crumpled blanket.

The two stood, staring, but then the _click!_ of a door upstairs caught their attention. They ran up the stairs, calling the children’s names. Papyrus’ bedroom door was undisturbed, Sans went to open the bathroom door only to find it locked.

“Go away!” Swap shouted from inside as the door handle rattled.

“Swap! What’s this all about?” Sans asked.

“I MUST INSIST YOU OPEN THIS DOOR IMMEDIATELY, BOY!” Papyrus shouted.

“Paps, easy.”

“I can take care of Blue all by myself! We don’t need you!”

Sans’ brow furrowed; what was with this sudden change of heart?

“Can’t you just use one of your shortcuts to get in there?” Papyrus asked gruffly.

“It’s probably not a good idea,” Sans countered.

“I shall break down the door, then!”

“Boss! Chill!” Sans sighed, pulling Papyrus away from the door a bit and lowering his voice. “Look, I dunno what’s got the kid so spooked all of a sudden, and he’s obviously being careful. Notice Blue isn’t making a sound? He’s probably still sleeping. Remember back when we were kids? We didn’t trust anyone, either.”

“Because everyone was out to kill us!”

“That’s what we thought. We were kids, we were scared, and no adult took the time to gain our trust. I can’t be sure what kind of world these two began growing up in, but since Blue was so friendly, I’m guessing it’s probably a lot nicer than ours, and yet, Swap is still suspicious.”

Papyrus sighed. “What do we do, then?”

“We try to gain his trust. Look, he can’t stay in the bathroom forever; not sure how long it’s been since the kid ate but between him losing so much magic with his arm injury and whatever else happened between him and Blue being separated and now, but he’s running on fumes.”

Papyrus nodded. “Okay, I ask again; what do we do?”

“I think you should do what you do best and make that awesome dinner you were planning. I’m going to try to talk to him and see where I get.”

Papyrus rubbed one arm, looking unsure, but sighing and nodding.

“Very well, brother. I shall make the best lasagna that Master Chef Papyrus can muster!”

Sans smiled. “You can do it, bro.”

“Nyeh, heh, heh!”

Papyrus was invigorated with his mission and went downstairs quickly to fulfill it. Sans went back to the bathroom door, looking at it from top to bottom before sighing and leaning his back against it and sliding to sit on the floor.

“This seems awfully familiar,” he murmured as he brought up one hand and rapped the back of his knuckles against the wood. “Knock, knock.”

There was a sniffle and a shuffle.

“C’mon, kid, it’s like, the law; you have to say who’s there.”

Another shuffle. Sans listened carefully and he was sure he heard a wince of pain before a shaky voice replied very, very softly, but very guarded.

“W-who’s there?”

“Doris.”

A pause. “Doris who?”

“Doris locked, that’s why I knocked!”

There was another pause, but then Sans heard a small snort. He knocked on the door again.

“Who’s there?”

“Atch.”

“Atch who?”

“Bless you!”

A small giggle. Sans knocked again.

“Who’s there?” Swap’s voice was stronger this time.

“Orange.”

“I know this one. Orange who?”

“Orange you gonna open the door?”

A small snort of laughter. “That’s not how it goes! And no!”

Sans sighed. “It was worth a shot. So, why the sudden change in heart, kid?”

“I heard you an’ Papyrus talkin’ and I can take care of Blue by myself!”

“I know you can, Swap,” Sans said gently. “And that is an amazing thing that you can do, especially since you yourself are so little.”

“I’m a big boy! I don’t need diapers like my brother!”

Sans chuckled. “That is true, thank the stars. But my point is, Swap, is that you don’t have to take care of Blue by yourself.”

“But I can!”

“You can, but honestly? You shouldn’t have to.”

There was silence. Sans sighed and leaned more heavily against the door.

“Listen to me, Papyrus; you are very brave and strong for taking care of Blue on your own. You know, I had to take care of my bro when he was a baby, too. I remember what it takes and I remember how difficult it is. But there is nothing that makes it all better than when your baby bro looks up at you with that smile, huh?”

There were a few sniffles. “Yeah.”

“Yeah. You will still be taking care of him, just, you also have Papyrus and me to help you. You won’t have to worry about finding food, my bro is a great cook. You won’t have to worry about finding a safe and warm place to sleep, there’s a fine couch downstairs, Blue has a crib in our bedroom, you can either sleep in my old room or squish into Pap’s racecar bed, I think we would fit.”

Swap giggled. “We’d be nothing but a pile of bones.”

“Maybe,” Sans chuckled. “So, whadya say? Wanna come out now?”

Silence again. Sans waited patiently.

“How do I know you won’t hurt us? How do I know you’re not tricking us?” Swap asked.

Sans nodded. “Yeah, you don’t know. I hate making promises, kid, but I’ll tell you, I’m willing to promise that Papyrus and I will take care of you both. You won’t have to worry about anything for a good, long while. We will do everything we can to make sure you are safe, happy, and that nothing tears you two apart again.”

Swap didn’t answer.

“Think on it, kid. I’m going to go downstairs for a bit. You come out when you like.”

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

“He still hasn’t come down?” Papyrus asked, taking the tray of lasagna out.

“Nah,” Sans said with a sigh, thumbing through a quantum physics book.

“Hm. I do not want him to go hungry.”

“Why don’t you take a plate up to him? Check in, see how he’s doing; I think if we show him we care but he can still have his space, maybe he’ll come to trust us.”

Papyrus gave a resolute nod before cutting a piece of the lasagna out, plating it, and heading for the stairs. He sat by the bathroom door and set the plate by his side. He knocked firmly.

"Who's there?" Swap called.

"IT'S THE GREAT AND TERRIBLE PAPYRUS!"

".... the great and terrible Papyrus who?"

Papyrus snarled. "THIS ISN'T ONE OF MY BROTHER'S HORRIBLE KNOCK KNOCK JOKES!"

"Oh."

Papyrus cleared his throat and lowered his voice. "Sorry, I did not mean to shout. I brought you a plate of my famous lasagna; aren't you getting hungry?"

"No."

"Are you certain?"

"Yes."

Papyrus frowned, then as he sighed, he brought his knees to his chest, wrapping his arms around his legs and resting his chin on his patella.

"You know, Sans took care of me very much the same way you are taking care of Blue," Papyrus said after a few moments of silence.

"Says him."

"It was not easy. Of course, I do not remember a lot from when I was little like Blue, but I remember what it was like when I was a little older. Sans worked very hard, I could see that, and he stood up for me and sometimes he got hurt for it."

"Not gonna happen to me! I'm strong!"

"I can tell. So is Sans. Despite this, though, I did wish there was someone to take care of Sans the way he took care of me, then maybe he wouldn't have some of the problems he has today. I think Blue, even being only a baby, probably wishes that someone would take care of you, because you deserve to be cared for and loved like you care and love for him."

Papyrus heard sniffling. "But what if they take Blue away from me?"

"I would never allow such a thing to happen! Neither would Sans! You and Blue will both be under our care, our brothers, and you will have no cooler skeleton in all the Ungerground as your caregiver."

It was then Papyrus noticed a quiet whimpering from inside; Blue was awake and Papyrus could tell that he was hungry.

"Papa! Papa!" Blue cried.

"I'm here, bro," Swap said.

But Blue wanted Papyrus, and the adult skeleton knew it.

"Hey, come on, you know I got you," Swap said.

Blue stopped crying but was making small whines and whimpering sounds. After a few minutes, Swap sighed, there was a click and the door to the bathroom opened.

"Papara!" Blue gurgled, holding out his arms to Papyrus.

As much as he wanted to, Papyrus didn't move to take the baby, noting that Swap was holding him tight around his middle with his good arm, his injured one just barely supporting the little skeleton's bottom. Blue was a baby, but he was still heavy, especially for a little skeleton like Swap.

"Do you want me to take him?" Papyrus asked. "Your arm is still injured, I don't want you to inadvertently injure it further."

As Blue was beginning to wiggle impatiently, and his arm was beginning to ache, he nodded.

There was a frightening moment when Swap nearly dropped Blue, but Papyrus moved forward quickly, not only able to take Blue in one arm but support Swap with the other to keep him from falling.

"I got you, both of you," Papyrus said, hugging them firmly.

Blue giggled and snuggled into Papyrus. Swap said nothing, but the tall skeleton could feel him trembling a little.

"Let's got to the kitchen; the hallway is no place to eat dinner!" Papyrus declared. "Swap, would you like me to carry you downstairs?"

"I'cn walk," he muttered.

Papyrus nodded, but then he found himself caught in a small dilemma; the plate of lasagna was still sitting by the wall. Leaving it there was unsanitary, but he didn't want to ask Swap to carry it - his arm was hurting and the poor child was still too low on magic - and Papyrus wanted to be sure he had both arms to support each child as they went down the stairs. It was a difficult decision, but one that Papyrus had to make. He left it alone, putting an arm gently around Swap, and carefully going down the stairs and into the kitchen.

Dinner was eaten with little drama. Swap seemed impressed with the high chair that Blue sat in, and was more impressed that the baby was moving on to using utensils to eat. Not that he was particularly good at it yet.

“Still messy, huh little guy?” Swap murmured, smiling at his brother.

“I BELIEVE UNDER MY MASTERFUL TUTELAGE, HE IS GETTING BETTER!” Papyrus declared.

Swap blinked at him. “Toot-a-what?”

“He’s teaching him,” Sans explained. “My bro is too cool.”

“NYEH HEH HEH!”

“MWEH HEH HEH!”

Swap stared between the three of them, shifting a little uncomfortably in his chair, and remaining quiet for the remainder of dinner.

Once the meal was done, Sans and Papyrus kept up their regular routine – Papyrus would put away dinner and clean up the kitchen while Sans took Blue upstairs for a bath.

“You can either hang out down here with Papyrus, or you can come upstairs with me while I bathe Blue,” Sans offered. “Or do whatever you want, kid, no pressure.”

“I can bathe Sa- I mean, Blue,” Swap murmured.

“Not with your arm still injured,” Sans gave him a serious look. “Actually, I’d like to try giving you another round of healing magic.”

“No, I’m okay.”

“Nonsense, kid.”

“Sans, I will assist you later,” Papyrus said, shooting him a look. “You have no magic to spare yourself.”

Sans shrugged. “Come on, Blue, you’re not getting any cleaner.”

Swap glanced between Sans as he went upstairs and Papyrus, who turned back to his cleaning, and sat in his chair, uncertain what to do.

“Where will we sleep?” he murmured.

“Blue, Sans, and I have been sharing my bedroom. Blue has a crib, and Sans and I have been sharing my bed,” Papyrus explained.

“Are you and Sans married?”

Papyrus dropped the dish he was washing. “OH MY GOD, NOT YOU TOO?!”

“I thought married monsters shared beds,” Swap mumbled, embarrassed now.

Papyrus sighed and picked up the dish to continue washing. “That may be, but I am willing to guess you and Blue always shared sleeping space?”

“Yeah, but, he’s a baby.”

“Hm. True. But no, Sans and I are not married, we both wanted to be close to Blue and we didn’t see the point in bringing his bed in. It’s filthy, anyway.”

“Oh.”

Papyrus finished rinsing the last dish and set it aside to dry and he looked over at Swap, who was tracing his fingers on the tabletop. Papyrus went over and put a hand gently on his shoulder.

“You can sleep in my bed, and by yourself, if you like. That way you and Blue can be in the same room. I don’t want you sleeping in Sans’ gross room and I don’t think sleeping on the couch is appropriate for a young, developing monster, however, at least for tonight, you have your choice.”

Papyrus tried to smile as kindly as he could, but Swap’s lack of reaction gave him the impression that he wasn’t doing too good of a job. He straightened, cleared his throat and folded his hands behind his back.

“Well, tomorrow we will settle everything that needs settling,” Papyrus said. “Get you some clothes, see about getting your own bed, decide where your bedroom will be, but of course, one step at a time.”

Swap silently nodded.

“I am almost done, here. Why don’t you go upstairs? I’m sure Blue doesn’t want to be without his cool big brother.”

Swap looked up at Papyrus, and whether the tall skeleton knew it or not, he was giving Swap a very sincere smile. Swap’s mouth quirked up slightly, he nodded, and shuffled towards the stairs. Papyrus chuckled and turned to grab a sponge to wash the high chair and table.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

Blue was bathed and changed into a fresh pair of pajamas, Swap was given a different shirt to wear, and he sat on the edge of the red racecar bed as he watched Sans and Papyrus go back and forth between both children, working seamlessly together, and soon, Sans was grabbing a book from a nearby shelf and making himself comfortable by the crib.

“What’s that?” Swap asked.

“Oh, this is a book I read to Paps when he was a babybones,” Sans explained, showing Swap the cover.

“ _’Peek A Boo with Fluffy Bunny?’_ ” Swap asked, sounding a little dubious.

“I still love it!” Papyrus declared. “The ending always gets me.”

“Blue seems to like it, too, so, we’ve been doing this every night,” Sans said.

“Would you mind if I sat next to you, Swap?” Papyrus asked.

“I guess not,” Swap said, moving over to give the other skeleton room.

Papyrus nodded a thanks and sat down carefully, sitting on the side of Swap that had the uninjured arm. Sans settled himself against the crib, opened the book, and began reading.

It didn’t take long for Blue to settle in to sleep, and Swap was making a valiant effort to stay awake but he was failing and quickly. He unconsciously leaned against Papyrus, who put his arm around him protectively. Papyrus glanced down, realizing that his own hand rested almost perfectly against Swap’s injured arm, and he gently invoked his healing magic. Sans glanced up at the slight glow of green, still continuing to read without interruption, giving Papyrus a meaningful look and a smile.

By the time the book was finished, both children were fast asleep and Papyrus was yawning, even as he carefully moved Swap fully onto the bed and covered him with the blankets, tucking him in.

Sans stood and put the book away before joining Papyrus, who was still standing next to his bed and looking down at Swap.

“So, were you like him?” Papyrus asked in a tone just above a whisper.

“Yeah,” Sans breathed. “Poor little guy.”

“Poor you,” Papyrus murmured. “At least they have us.”

Papyrus looked over and reached down to grab Sans’ hand. Sans smiled and squeezed his hand back. Words weren’t necessary between them now.

“So,” Sans murmured after a moment. “Where are we going to sleep?”

Papyrus sighed. “I don’t know, we better figure that out.”

The two turned to leave, shutting off the light, but when they opened the door, they heard a small sob.

“Don’t leave me,” Swap said quietly.

The two brothers glanced at each other and went back to the bed. Swap was still asleep, but he was apparently having a nightmare.

“Please, please don’t leave me alone, not again, please,” he was muttering over and over, words broken by small sobs.

“Shh, Swap, we’re here,” Papyrus murmured, dropping to his knees next to the bed and passing a hand over Swap’s skull.

“We’re here for ya, kiddo,” Sans whispered.

Swap’s sobs faded into whimpers.

“We can’t leave,” Papyrus said.

“We don’t have to,” Sans said, sitting on the floor with his back against the bedframe. “I guess this is where we’re spending the night.”

Papyrus nodded resolutely, also turning and sitting on the floor. “Swap, we are here, we will protect you.”

A small shift in the blankets, a moment later the whimpers faded, and Swap was sleeping peacefully once more.

Sans yawned, leaning comfortably against Papyrus, who scoffed, but then put an arm around his brother, and soon enough, the two adults were dozing as well.

* ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ *

Swap blinked awake light began to filter through the windows. He gasped and sat up, immediately frightened by the unfamiliar surroundings, but then settling when he saw Blue sitting up in his crib, happily playing quietly with a stuffed toy.

As the memories from yesterday’s events came back, Swap took a deep breath, and then he noticed the two adult skeletons sleeping by the bed, leaning against one another, both snoring softly.

“Hey, you okay, lil’ bro?” he said soflty.

Blue looked up and giggled when he saw his brother awake and crawled to the edge of the crib, gripping onto the wooden bars and pulling himself to his feet.

“Papa pa!” Blue gurgled. He clapped in his excitement, falling onto his bottom again.

Swap smiled. “Still haven’t gotten the hang of standing and walking, huh?” he chuckled. He looked down at his caretakers and then back up at Blue. “So, what do you think of these two nerds?”

“Sa! Sa! Papara!” Blue squealed.

“Yeah, you seem to like them,” Swap said with a sigh. “Do you like them more than me, now?”

“Papara! Papara!” Blue shouted, grabbing onto the bars of the crib and shaking them with all his little might.

With a slight start, the two adult skeletons woke up.

“Morning, kid,” Sans said, grinning up at Swap. “How you feeling?”

“All right,” Swap said with a shrug.

“How does your arm feel?” Papyrus asked.

Swap blinked and moved his arm. “Huh, it doesn’t hurt at all.”

“Good, you’re still gonna take it easy though, kiddo,” Sans said.

Sans’ bones popped as he stretched his back while Papyrus tried to hide the uncomfortable look as he shifted.

“I, uhm, I’m sorry, I think I took your bed,” Swap murmured, looking at the floor sheepishly.

“Pfft, no worries, kid, I had Paps here; he’s nothing but bones, but he makes a decent pillow.”

“Shut up, Sans,” Papyrus said, standing up to leave Sans falling flat on the floor unceremoniously.

“Ow.”

Swap hid a small giggle behind his hand.

“RISE AND SHINE, BROTHERS!” Papyrus said loudly, making Sans and Swap wince, and picking up Blue. “WE HAVE A LOT TO DO TODAY! THERE IS TRAINING TO BE DONE! DECISIONS TO BE MADE! PURCHASES TO BE… well… purchased.”

“Training?” Swap said.

“Yeah, Papyrus is going to be in the Royal Guard one day, and he thinks Blue would make a good member of the Royal Guard as well, so, he’s been training him,” Sans explained.

“But he can barely stand,” Swap muttered.

“Actually, he’s been getting better at standing,” Sans said. “It’s walking that seems to be stumping the little guy.”

Swap followed them downstairs and sat quietly at the table as breakfast was prepared. It felt strange, as the addition of Swap didn’t seem to faze the adult skeletons; they didn’t forget to give him a plate, asked few questions when it came to his preferences (though they didn’t have much variation available), and Swap was fascinated by the seamless way they worked about the kitchen, as if they were a team.

It made Swap a little uncomfortable with how happy Blue seemed to be. He sat giggling in his chair, making gurgling and coos, Sans especially seemed to dote a lot on him. Sans and Papyrus each had tried to show Swap a little bit of extra attention, but he only stared at the piece of cheese that Sans slipped him and flinched when Papyrus went to pat him on the head. Both figured Swap wasn't ready to trust and continued with breakfast.

“Here you go, bud,” Sans said to Blue, pulling the high chair closer and starting to feed him baby cereal.

“Mah mah mah mah!” Blue babbled, reaching for the spoon when Sans got close with it.

“NOT THIS MORNING, BLUE! WE CANNOT AFFORD THE TIME TO BATHE YOU AFTER BREAKFAST!” Papyrus said as he served plates of the leftover lasagna.

Blue made a face, but he accepted and ate with a slight hint of reluctance.

“He really likes you guys,” Swap murmured. “He didn’t like strangers back home, definitely wouldn’t have let them feed him.”

“HE HAS HAD TIME TO GET USED TO US,” Papyrus said with a dismissive wave.

"Is this the only thing you know how to make?" Swap asked, poking at the food on his plate.

"Yes, Captain Undyne had said that I must master lasagna before I move forward," Papyrus explained.

"Just think of the _pasta_ -bilities once he gets this recipe nailed," Sans said with a grin.

"NOT AT THE BREAKFAST TABLE!"

"Ba ba ah bah!" Blue babbled disapprovingly, refusing to take another offered spoonful of cereal.

Sans snickered and continued to try to get Blue to eat. Swap smiled a little, but went back to poking at the small pile of pasta, sauce, and cheese.

Papyrus noticed Swap wasn’t eating, but he didn’t know what to say so he remained silent. Sans didn’t pick up on it until nearly the end of the meal.

“Feelin’ okay, kid?” Sans asked.

“Yeah, just not hungry,” Swap mumbled.

“Okay, if you’re sure,” Sans said.

“It just occurred to me, what is Swap going to wear? We are training in the snow and it will do him no good to catch cold!” Papyrus said.

“Yeah, especially while your arm is still healing,” Sans said, leveling a serious look at Swap.

“But it feels fine, see?” he lifted the injured arm and moved it about, but then winced when he went too far and recoiled in his chair.

“See? Looks fine, feels mostly fine, but isn’t fine, yet, and that’s okay. Katherine should have some clothes that’ll fit, but your sweater is still all messed up.”

“So, what do I do?” Swap mumbled, bringing his feet into the seat of the chair and almost seeming like he was trying to disappear into the over-sized t-shirt he wore.

“Probably best if we wrap you up really good and you let us carry you.”

“But I’m a big boy!”

Sans smiled, a quick flash of Papyrus at that age passed over his eyes briefly.

“Yes, you are,” he said. “And big boys also know when to ask for help.”

“I don’t need you to carry me!”

“SWAP!” Papyrus started, getting to his feet.

“Hey, whoa,” Sans caught Papyrus’ attention. “I’ll take care of Swap. Why don’t you get Blue changed and you carry him, since he’s training with you and all?”

Papyrus nodded, immediately sweeping over to Blue and taking him out of the high chair.

“MWEH HEH HEH!” Blue giggled.

‘NYEH HEH HEH!” Papyrus answered, nuzzling the baby’s face before leaving the kitchen.

Swap frowned, a hand going to his sternum; his baby brother was even beginning to sound like them…

“Here’s the deal, kid,” Sans’ voice brought Swap’s attention back. “We’ll get you wrapped up in some more of my old junk. If you can walk, awesome. But if you fall even once, I get to carry you.”

Swap scowled. “I bet I won’t fall at all!”

“Careful, though, I cheat,” Sans winked. “Maybe there will be a bone in the way.”

“Yeah? Maybe there will be a bone in _your_ way.”

“Ah, c’mon, kid, funny bone broken or something?”

“I thought it was _humerous._ ”

The two continued to joke and pun through getting dressed, and soon the four were ready to go out. Swap looked a little odd dressed in Sans’ old clothes, the baggier parts being wrapped and tied around him with whatever they could find (an old shoelace here, a bathrobe tie there), and they began to make their way into town.

If the skeleton brothers got odd looks before with Blue, they were all but astonished at the addition of Swap, though it was hard to tell because it Swap was an older child than Blue or the odd assortment of clothing he sported.

“Is that…?”

“….. another pup?”

Swap immediately froze as the Dogi approached.

“What are you two doing?” Papyrus asked, stiffening and straightening up, trying to look commanding even with Blue wrapped around him with the black band.

“Day off,” Dogamy said.

“Captain Undyne approved,” Dogaressa added.

“I smell….”

“…. a weird puppy?”

They moved closer to Swap, who Sans could see starting to shake.

“Heel,” Sans said, moving to put himself between Swap and the canines. “Listen, guys, this one’s a little shaken up. He’s the big brother of the baby, along with us.”

“So it is…”

“…. another pup!”

They tried to press forward again, but Sans put a hand on their shoulders to keep them in their spot.

“Give the kid some space, a’ight? I promise you can sniff at him when he’s feeling more comfortable.”

Dogaressa gave Sans a scandalized look. “What is wrong with you?”

“Huh?”

“The puppy is injured!” Dogamy supplied.

“Yeah, we know.”

“Heal him!” Dogaressa demanded.

“We did!”

The two dogs were now growling at Sans.

“S-stop!” Swap spoke up.

They all turned to look at him.

“Leave him alone! Just… just please, leave him alone,” Swap’s voice faded into a murmur.

“The pup….”

“…. has spunk.”

“Take good care of him.”

“Or else.”

The Dogi gave Sans one last growl, a smile to Swap, and they passed Papyrus to salute him and nuzzle at Blue, who giggled and pat their snouts.

“What gives, Boss?” Sans whirled on Papyrus. “You were just gonna it there and let the mutts chew on me?”

“I half expected you to _throw them a bone!_ Nyeh heh heh,” Papyrus chuckled and continued on.

“You smooth motherff…” Sans glanced back at Swap, “farmer. Yeah. You okay, kid?”

Swap nodded.

“Good, let’s go.”

“S-sans?”

“Yeah, kid?”

“I can’t move.”

Swap was trembling. Sans gave him a sympathetic smile and moved over to scoop him into his arms.

“That was really brave of you, standing up for me like that. Thanks, bud,” Sans said.

Swap remained silent.

~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~

The visit to Katherine's store went quickly; while the rabbit monster quipped that the two adult skeletons had been busy, Swap dug into the shelves filled with clothes and pulled out an outfit that would fit him; he even found a dark orange hoodie similar to the one Sans found him in, though this one had a blue stripe around its center. He left a mess, much to Katherine's dismay, but she still smiled at the little skeleton and told him to not worry.

Sans snickered, knowing that if it has been him (or probably anyone else), Katherine would have had a major fit and threaten the offender with a fate worse than death if they didn't rectify the situation.

"She likes ya, kid," Sans said as they left the shop.

Swap was still silent.

They hiked out into the woods where Papyrus had set up his "Super-Secret Training Facility" (nyeh heh heh). Not only was the training dummy still a part of it, but there seemed to be a small obstacle course - an arrangement of snow poffs, some ropes hanging from a nearby tree, one had what looked like an axe attached to it but the blade was covered by a pillow wrapped in a blanket. In fact, many of the ropes had soft items swinging from them, including a stuffed white toy dog.

"IMPRESSIVE, YES?" Papyrus asked.

Swap only stared.

"May be too much cool for him to handle, Boss," Sans said. "C'mom, I have a cheering section for us."

Swap's eyes didn't leave Papyrus and Blue fully as he shuffled after Sans, watching Fell carefully unwrap the black material used to keep Blue close to him. He set Blue on the ground, took a moment to wrap up the material and set it aside before scooping up the baby again.

"TODAY WE SHALL CONTINUE BATTLE TRAINING, BLUE!" Papyrus declared.

"Not again," the training dummy grumbled. "I know this is a living, but... hey, you two had another brat?"

Swap, suddenly feeling shy, began to move behind Sans without trying to make it look like he was trying to hide.

" _Stuff_ it, pal," Sans said.

"Make me, bone boy!"

"C'mon, are you _mannequin_ or a mouse?"

Swap snickered.

"ENOUGH! WE HAVE IMPORTANT TRAINING TO ATTEND TO!" Papyrus growled. 

“BAH BA BA BAH BAH!” Blue also protested.

Sans flopped down in the area of snow that seemed to be more pat down than the rest. Swap reluctantly moved to sit next to him, though was sure to keep quite a few inches of distance between them.

“I don’t bite, kid,” Sans reminded him.

Swap seemed to ignore him and instead focused on his brother. Sans followed the child’s eyes, and smiled.

“It’s okay, he won’t get hurt, I swear,” Sans said.

Swap remained silent.

“COME ON, BLUE, SHOW ME WHAT YOU GOT! TEAR THE DUMMY APART!” Papyrus cried encouragingly.

“What are you gonna do? Crawl over to hug me again? He’s a joke, still not able to walk,” the dummy jeered.

Blue scowled and with a determined grunt, he moved himself so that he could get to his feet.

“YES, BLUE, YES!” Papyrus cried excitedly. “SHOW HIM YOUR COOL WALKING ATTACK!”

Blue barely made a step before he fell face first in the snow. Papyrus moved quickly to right the baby and wipe the snow from his face.

“C’mon kid, try again!” Sans shouted.

Blue kept standing up and falling. If Papyrus tried to help him, he wailed. Sans and Swap watched silently, both rooting for the baby to reach his goal as the Training Dummy continued to tease him.

“Why does he even bother?” Swap murmured.

“What do you mean?”

"Because he's gotta learn," Sans said.

"What's the point of anything?!"

Sans, startled by the outcry, turned to stare at the young child and was shocked to find tears trailing down the little face as he sniffed, obviously trying to keep just that from happening.

"Hey, Swap, what's up, buddy?" Sans shuffled closer to the little skeleton.

"It's not fair! Blue is _my_ little brother and he likes you guys better than me!" Swap wailed.

"Aw, that's not true," Sans said.

"Yes, it is! He wanted Papyrus last night, not me! He wanted you to read him his bedtime story, he lets you feed him, and... and..."

Swap's voice wavered as he dissolved into silent crying. Sans was at a loss, Papyrus and Blue were also staring.

Blue looked up at Papyrus, then over to his brother, and the little face set into a look of determination harder than ever before. The baby rolled over into his knees, pushing himself up onto his feet, and he stood wavering, but proud, and waited until Swap caught his eye and looked up.

Blue took a step, shaky and unsteady, but still a step. Then he took another, and then, another. The other three watched silently as the baby monster continued to take shaky step after shaky step towards his older brother.

“That’s right, Blue,” Papyrus whispered, clenching his fists and nearly vibrating with excitement. “Do it, do it!”

Sans chanted his cheers for Blue in his head, glancing over at Swap as he held his breath.

Blue was grinning by the time he reached Swap and all but collapsed into the little skeleton’s waiting arms.

“PAHPAHRAHS! BRAH BRAH! MWEH HEH HEH!” Blue giggled, wriggling excitedly in Swap’s arms.

“B-blue, you, you walked,” Swap murmured, still sniffling. “You walked, for me?”

Blue seemed to nod, which made Swap start to laugh, and he hugged the baby tightly.

“You’re so cool, baby bro!” Swap said.

“Way to go, lil’ guy,” Sans said, moving over to the two to pat them both on the head.

“He’s great,” Swap sniffed.

“I mean you,” Sans said with a wink. “I don’t know how much longer it would have taken Blue to figure it out if you weren’t here.”

“You think so?”

“I know so.”

“MY BROTHERS!” Papyrus wrapped his long arms around all three of them and lifted them off the ground. “THIS IS WONDERFUL! I KNEW BLUE WOULD BENEFIT FROM MY MASTERFUL TRAINING AND SWAP’S ENCOURAGEMENT! WELL DONE!”

“Aw, I didn’t do anything,” Swap murmured, but blushing a little at the compliment.

“NONSENSE! YOU ARE AN AMAZING BIG BROTHER! YOU WOULD ALSO MAKE A GREAT ADDITION TO THE ROYAL GUARD! YOU SHOULD BEGIN TRAINING WITH BLUE AT ONCE!”

“Heh, I don’t know, Papyrus, I don’t think I have a thick enough skin for something like that.”

Sans snorted.

“PAH!” Blue yelped, smacking Swap in the forehead.

“….. IF YOU WEREN’T HOLDING BLUE AND WERE NOT MY PRECIOUS LITTLE BROTHER, I WOULD DROP YOU,” Papyrus snarled.

~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~ * ~

“And so Fluffy Bunny promised he would teach his friends how to play Hide and Seek, and they remained the best of friends forever. The end.”

Sans shut the book and glanced over his shoulder, not surprised to see Blue fast asleep, then looked over to the bed where Papyrus was dozing, his elbow on the edge of the bed, and Swap also asleep, one arm hanging off the mattress.

“Heh,” Sans chuckled, closing the book, putting it away, and then moving Swap’s arm back on the mattress and tucking him in before shaking Papyrus’ shoulder gently. “C’mon, Pap, let me get you comfy on the couch, probably not a good idea to sleep on the floor again.”

“Hmm? Oh, right,” Papyrus said sleepily, beginning to stand up.

“Sans? Papyrus?”

The two were stopped by Swap’s little voice.

“What’s up?” Sans said.

“Uhm, maybe you two could share the bed with me this time? It’s too big for me,” Swap murmured.

The two older skeletons exchanged a glance. Papyrus looked very, very pleased and Sans was grinning wider than ever.

“As long as you’re sure, kid,” Sans said.

“I, I am.”

“I accept your proposal!” Papyrus said.

Swap snickered. “Papyrus, I thought you were married to Sans.”

“That’s not what I meant and no I am not!”

With a few more giggles between them, Sans and Papyrus climbed into bed, lying comfortably on either side of Swap. Swap snuggled into the blanket and sighed happily before beginning to doze off again.

“Goodnight, Brother Sans, Brother Papyrus,” Swap murmured as he drifted into sleep.

Papyrus quivered happily. “Sans! Did you hear him?”

“Heh, yeah bro. I did.”

**Author's Note:**

> Like what you read? Please check out my social media for more fun!  
> [ My Tumblr](https://soloshikigami.tumblr.com/)  
> [ My Twitter](https://twitter.com/SoloShikigami)


End file.
